Dual sensor electrodes for providing enhanced resuscitation feedback

ABSTRACT

A system for facilitating resuscitation includes: a first electrode assembly having a therapy side and a first motion sensor; a second electrode assembly having a therapy side and a second motion sensor; processing circuitry operatively connected to and programmed to receive and process signals from the first and second motion sensors to estimate at least one of a chest compression depth and rate during administration of chest compressions and to compare the chest compression depth or rate to a desired range; and an output device for providing instructions to a user to administer chest compressions based on the comparison of the estimated chest compression depth or rate to the desired range. One or both of the electrode assemblies may be constructed so that the conductive therapeutic portion is able to maintain substantial conformance to the anatomy of the patient when coupled thereto. For example, at least a portion of the flexible electrode pad may be able to flex from a more rigid sensor housing, or the sensor housing itself may be relatively small compared to the flexible electrode pad so as not to cause lift off of the therapeutic side from the patient.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationSer. No. 62/242,749, entitled “Dual Sensor Electrodes for ProvidingEnhanced Resuscitation Feedback”, filed Oct. 16, 2015, the entirecontents of which are incorporated herein by reference.

BACKGROUND Field

The present disclosure is related to cardiac resuscitation and, morespecifically, to systems and techniques for assisting rescuers inperforming cardio-pulmonary resuscitation.

Description of Related Art

Defibrillators are commonly used to treat Sudden Cardiac Arrest byapplying a defibrillating shock to the heart of a cardiac arrest patientvia electrodes placed on the chest of the patient. The ECG signal of acardiac arrest patient, properly measured and analyzed, provides astrong indication of whether the patient's heart is exhibiting ashockable rhythm or a non-shockable rhythm. A shockable rhythm refers toan aberrant ECG signal where a defibrillation shock is advised forrestoration of a normal heartbeat, while a non-shockable rhythm refersto an ECG signal where a defibrillation shock is not advised.Ventricular fibrillation, for example, is a shockable rhythm, whilepulseless electrical activity is an example of a non-shockable rhythm.Defibrillators are also capable of treating other dysrhythmias(irregular heartbeats), such as atrial fibrillation, bradycardia, andtachycardia. An ECG signal may be obtained through electrodes placed onthe chest of the patient, and the defibrillating or cardioverting shockmay be applied through the same electrodes.

During resuscitation, treatment protocols recommended by the AmericanHeart Association and European Resuscitation Council advise for therescuer to regularly check the patient's pulse or to evaluate thepatient for signs of circulation. If no pulse or signs of circulationare present, the rescuer may be often instructed to perform CPR on thevictim for an appropriate period of time between shock analyses, whereCPR involves applying both chest compressions and ventilations to thevictim. Chest compressions and/or ventilations may be monitored duringthe course of CPR, for example, through systems and technologies thatincorporate real-time CPR feedback (e.g., REAL CPR HELP® marketed byZOLL® Medical Corporation) and which may implement resuscitationassemblies (e.g., CPR-D-PADZ®, CPR STAT-PADZ® marketed by ZOLL® MedicalCorporation) having a sensor for obtaining CPR related information formanual CPR providers. For example, ZOLL's CPR-D-PADZ® and CPR STAT-PADZ®include a pair of electrode pads and a single chest compression sensor.

SUMMARY

According to one aspect of the present disclosure, provided is a systemfor facilitating resuscitation that comprises: a resuscitation assemblycomprising: a first electrode assembly comprising a therapy side and afirst motion sensor; a second electrode assembly comprising a therapyside and a second motion sensor; processing circuitry operativelyconnected to the resuscitation assembly and configured to identify theresuscitation assembly as one of a pediatric or adult resuscitationassembly based on an identification signal, receive and process signalsfrom at least one of the first and second motion sensors to estimate atleast one of a compression depth and rate (or other chest compressionparameter such as release velocity) during administration of chestcompressions, and receive and process signals from the first and secondelectrode assemblies to determine whether electrotherapy is required andadjust electrotherapy based on the identification of the resuscitationassembly as pediatric or adult; and an output device for providing oneor more chest compression parameters including at least one of theestimated compression depth and the estimated compression rate for auser, wherein the output device is configured to adjust presentation ofthe one or more chest compression parameters based on whether theresuscitation assembly is identified as pediatric or adult.

In one example, the processing circuitry may be configured to determinea placement orientation of the first electrode assembly and the secondelectrode assembly on a patient. For example, the first electrodeassembly may be positioned on a first portion of the patient's anatomyand the second electrode assembly may be positioned on a second portionof the patient's anatomy in an anterior-posterior orientation. In such aconfiguration, the first portion of the patient's anatomy may be asternum of the patient and the second portion of the patient's anatomymay be a back of the patient. Alternatively, the first electrodeassembly is positioned on a first portion of the patient's anatomy andthe second electrode assembly is positioned on a second portion of thepatient's anatomy in an anterior-anterior orientation such that thefirst electrode assembly is a sternal electrode and the second electrodeassembly is an apex electrode. In such a configuration, the firstportion of the patient's anatomy may be a right side of a chest of thepatient between the armpit and the sternum and the second portion of thepatient's anatomy may be a left side of the chest of the patient overlower ribs of the patient. In another example, the processing circuitrymay be configured to adjust at least one of a displayed ECG signal and apacing vector based on the determined placement orientation of the firstelectrode assembly and the second electrode assembly.

In one example, at least one of the first motion sensor and the secondmotion sensor is separable from the respective first or second electrodeassembly. For instance, the first motion sensor may be separable fromthe first electrode assembly or the second motion sensor may beseparable from the second electrode assembly.

In another example, the estimated chest compression depth may becalculated by subtracting a distance traveled by the second motionsensor from a distance traveled by the first motion sensor. The firstmotion sensor may be configured to produce a first signal representativeof acceleration caused by compressions and the second motion sensor isconfigured to produce a second signal representative of acceleration dueto movement on a compressible surface. The processing circuitry may beconfigured to utilize signals from the first motion sensor and thesecond motion sensor to determine depth of compression when an infant orneonatal patient is squeezed from both the front and back during CPR.

In one example, the resuscitation assembly may include at least one of amemory and a resistor from the identification signal is based. Theprocessing circuitry may be configured to adjust a shock algorithm basedon the identification of the resuscitation assembly as pediatric oradult. The processing circuitry may be configured to compare at leastone of the estimated compression depth and the estimated compressionrate to a desired range, and the output device is configured to displayat least one of the estimated compression depth and the estimatedcompression rate and provide chest compression prompting for the userwhen the resuscitation assembly is identified as adult. The outputdevice may be configured to display at least one of the estimated depthand the estimated rate without providing chest compression prompting forthe user when the resuscitation assembly is identified as pediatric.

In one example, the processing circuitry and the output device may beprovided in an external defibrillator. At least one of the firstelectrode assembly and the second electrode assembly may include aflexible electrode layer including the therapy side. In another example,at least one of the first electrode assembly and the second electrodeassembly includes a sensor housing attached to the electrode layer at anattachment region. In such an example, the sensor housing may at leastpartially enclose the first or second motion sensor. At least a portionof the electrode layer may be constructed and arranged to deflect fromthe sensor housing at a location away from the attachment region suchthat the electrode layer substantially conforms to the patient'sanatomy. The sensor housing may be laminated with the electrode layer.The sensor housing may include a padding material. In one example, thesensor housing may include a plurality of layers comprising the paddingmaterial.

The output device may be configured to provide instructions to a userfor a surface upon which the patient is positioned to be changed basedon information sensed from the first and second motion sensors. In oneexample, at least one of the first motion sensor and the second motionsensor comprises an accelerometer capable of measuring acceleration inmultiple directions. In such an example, the processing circuitry may beconfigured to estimate a difference in orientation between the firstelectrode assembly and the second electrode assembly. More specifically,the processing circuitry may be configured to estimate an angle relativeto a vertical axis of the patient at which a user is administering chestcompressions during CPR based on the signals received from the first andsecond motion sensors. The output device may be configured to provideinstructions to a user for administering chest compressions based on theestimation of orientation between the first and second electrodeassemblies.

In another example, the processing circuitry may be configured toestimate rate of ventilations applied to the patient (e.g., from signalsarising from one or more of the motion sensors, such as the anteriormotion sensor). In such an example, the output device may be configuredto provide instructions to a user for administering ventilations to thepatient based on the estimated rate of ventilations.

In yet another example, at least one of the first electrode assembly andthe second electrode assembly may include a conductive gel having anactive area for electrotherapy of approximately 15-80 cm².Alternatively, at least one of the first electrode assembly and thesecond electrode assembly may include a conductive gel having an activearea for electrotherapy of approximately 50-150 cm². At least a portionof the first electrode assembly or the second electrode assembly may beradiolucent. The resuscitation assembly may include a cable extendingfrom at least one of the first electrode assembly and the secondelectrode assembly toward the processing circuitry. The cable mayinclude the processing circuitry for estimating at least one of thecompression depth and compression rate. The cable may be a substantiallyflat cable.

In yet another example, at least one of the first electrode assembly andthe second electrode assembly may include a conductive gel having anactive area for electrotherapy of approximately 15-80 cm².Alternatively, at least one of the first electrode assembly and thesecond electrode assembly may include a conductive gel having an activearea for electrotherapy of approximately 50-150 cm². At least a portionof the first electrode assembly or the second electrode assembly may beradiolucent. The resuscitation assembly may include a cable extendingfrom at least one of the first electrode assembly and the secondelectrode assembly toward the processing circuitry. The cable mayinclude the processing circuitry for estimating at least one of thecompression depth and compression rate. The cable may be a substantiallyflat cable.

According to another aspect of the present disclosure, provided is asystem for facilitating resuscitation. The system comprises: aresuscitation assembly comprising: a first electrode assembly comprisinga therapy side and a first motion sensor; a second electrode assemblycomprising a therapy side and a second motion sensor; processingcircuitry operatively connected to the resuscitation assembly andconfigured to: receive and process signals from at least one of thefirst and second motion sensors to estimate at least one of acompression depth and rate during administration of chest compressions,and determine a placement orientation of the first electrode assemblyand the second electrode assembly on a patient; and an output device forproviding guidance to a user to administer chest compressions based onthe estimated chest compression depth or rate and the determinedplacement orientation of the first and second electrode assemblies.

According to yet another aspect of the present disclosure, provided is asystem for facilitating resuscitation, comprising: a resuscitationassembly comprising: a first electrode assembly comprising a therapyside and a first motion sensor, and a second electrode assemblycomprising a therapy side and a second motion sensor; processingcircuitry operatively connected to the resuscitation assembly andconfigured to receive and process signals from at least one of the firstand second motion sensors to estimate at least one of a compressiondepth and rate during administration of chest compressions; and anoutput device for providing guidance to a user to administer chestcompressions based on the estimated chest compression depth or rate. Atleast one of the first motion sensor and the second motion sensor isseparable from the respective first or second electrode assembly.

The first motion sensor may be separable from the first electrodeassembly and/or the second motion sensor may be separable from thesecond electrode assembly. For example, the first electrode assembly orthe second electrode assembly may include a pouch within which therespective first or second motion sensor is removably held. In anotherexample, at least one of the first motion sensor and the second motionsensor is adhesively coupled to the respective first or second electrodeassembly.

According to another aspect of the present disclosure, provided is aresuscitation assembly for use with a defibrillator that comprises: aflexible electrode pad having a therapy side; a sensor housing attachedto the electrode pad; and a motion sensor at least partially enclosedwithin the sensor housing. The sensor housing has greater rigidity thanthe flexible electrode pad. At least a portion of the flexible electrodepad is configured to flex from the sensor housing such that theelectrode pad substantially conforms to an anatomy of the patient whencoupled to the patient.

The sensor housing may be coupled to the flexible electrode pad at anattachment region on the non-therapy side. In one example, theattachment region may be located in a central region of the flexibleelectrode pad. In another example, the attachment region may be locatedat least one of a central upper region and a central lower region. Instill another example, the attachment region may be located along atleast a portion of the periphery of the flexible electrode pad. Theflexible electrode pad may be configured to flex from the sensor housingat a location away from the attachment region.

The flexible electrode pad may comprise a flexible base layer (e.g.,made of a foam, thin polymeric material, electrode backing, and/or otherflexible material) having a flexible electrode positioned on the therapyside. The therapy side may include a conductive material configured toprovide a therapeutic treatment to the patient. The sensor housing mayinclude a protective covering, such as a casing for the motion sensor.In one example, the sensor housing may be comprised of two or morelayers. The two or more layers may be laminated to each other. Inanother example, the sensor housing may comprise a padded material. Thesensor housing may include a plurality of layers comprising the paddedmaterial. The one or more electrode assemblies may comprise sections ofdiffering thickness.

In one example, the motion sensor is an accelerometer, such a three-axisaccelerometer. The motion sensor may be encapsulated in a polymericmaterial to provide protection from a surrounding environment. Thesensor housing may be configured to distribute compressive forces causedby chest compressions during cardiopulmonary resuscitation (CPR)substantially evenly across the flexible electrode pad. In one example,the sensor housing may be integrated into the flexible electrode pad. Inanother example, the sensor housing may be adhered to the flexibleelectrode pad at the attachment region.

According to another aspect of the present disclosure, provided is aresuscitation assembly for use with a defibrillator that comprises: aflexible electrode pad having a therapy side configured to substantiallyconform to the patient's anatomy; a sensor housing coupled to theelectrode pad, wherein a projected contact area between the sensorhousing and the electrode pad is less than approximately 50 cm²; and amotion sensor coupled with the sensor housing.

In one example, the projected contact area between the sensor housing orcasing and the electrode pad may be between approximately 10-50 cm². Themotion sensor may be located over a periphery of the conductivematerial. In another example, the motion sensor may be located over acentral region of the conductive material.

The motion sensor may be a three-axis accelerometer. In one example, themotion sensor may be encapsulated in a casing or covering that includesa suitable material such as a polymeric material to provide protectionfrom a surrounding environment. In another example, the motion sensormay be at least partially enclosed within the sensor housing. The sensorhousing may have a greater rigidity than the flexible electrode pad. Atleast a portion of the flexible electrode pad may be configured to flexfrom the sensor housing such that the electrode pad substantiallyconforms to an anatomy of the patient when coupled to the patient.

According to still another aspect of the present disclosure, provided isa resuscitation assembly for use with a defibrillator that comprises twoor more electrode assemblies. Each electrode assembly comprises: aflexible electrode pad that comprises a therapy side and a non-therapyside; and a motion sensor within a sensor housing that is coupled to theflexible electrode pad. At least a portion of the flexible electrode padis configured to substantially conform to an anatomy of a patient whenplaced on the patient. The two or more electrode assemblies are coupledto each other.

For at least one of the electrode assemblies, the sensor housing may bemore rigid than the flexible electrode pad. In addition, for at leastone of the electrode assemblies, the sensor housing may be coupled tothe flexible electrode pad at an attachment region on the non-therapyside. In one example, the attachment region may be located at a centralregion of the flexible electrode pad. The sensor housing may be adheredto the flexible electrode pad at the attachment region.

For at least one of the electrode assemblies, the sensor housing mayinclude a protective covering or casing for the motion sensor. In oneexample, for at least one of the electrode assemblies, the sensorhousing may comprise a padded material. For at least one of theelectrode assemblies, the motion sensor may include an accelerometer. Inanother example, for at least one of the electrode assemblies, thesensor housing may be integrated with the flexible electrode pad.

According to another aspect of the present disclosure, provided is asystem for facilitating resuscitation that comprises: a first electrodeassembly comprising a therapy side a first motion; a second electrodeassembly comprising a therapy side and a second motion sensor;processing circuitry operatively connected to and programmed to receiveand process signals from the first and second motion sensors; and anoutput device for providing instructions to a user for a surface uponwhich the patient is positioned to be changed based on informationsensed from the first and second motion sensors.

In one example, the first motion sensor may be configured to produce afirst signal representative of acceleration caused by compressions andthe second motion sensor may be configured to produce a second signalrepresentative of acceleration due to movement on a compressiblesurface. A chest compression depth may be calculated by subtracting thesecond signal representative of acceleration caused by movement on acompressible surface from the first signal representative ofacceleration due to compression.

In one example, the first electrode assembly is positioned on a firstportion of the patient's anatomy and the second electrode assembly ispositioned on a second portion of the patient's anatomy in ananterior-posterior orientation. In such an example, the first portion ofthe patient's anatomy may be a sternum of the patient and the secondportion of the patient's anatomy may be a back of the patient.Alternatively, the first electrode assembly and the second electrodeassembly may be configured to be positioned on the patient in ananterior-anterior orientation. The processing circuitry and the outputdevice may be provided in an external defibrillator.

According to still another aspect of the present disclosure, provided isa system for facilitating resuscitation that comprises: a firstelectrode assembly comprising a therapy side and a first motion sensor;a second electrode assembly comprising a therapy side and a secondmotion sensor, wherein at least one of the first motion sensor and thesecond motion sensor comprises an accelerometer capable of measuringacceleration in multiple directions; processing circuitry operativelyconnected to and programmed to receive and process signals from thefirst and second motion sensors to estimate a difference in orientationbetween the first electrode assembly and the second electrode assembly;and an output device for providing instructions to a user foradministering chest compressions based on the estimation of orientationbetween the first and second electrode assemblies.

In one example, the processing circuitry may be configured to estimateat least one of a chest compression depth and rate (and/or otherparameter such as release velocity) during administration of chestcompressions and to compare the chest compression depth or rate (orother parameter such as release velocity) to a desired range based onthe received signals from the first and second motion sensors. Theoutput device may be configured to provide instructions to a user for asurface upon which the patient is positioned to be changed based oninformation sensed from the first and second motion sensors. Theprocessing circuitry may be configured to estimate an angle relative toa vertical axis of the patient at which a user is administering chestcompressions during CPR based on the signals received from the first andsecond motion sensors.

In one example, the output device may be configured to provideinstructions to a user for administering chest compressions based on theestimation of orientation between the first and second electrodeassemblies. In another example, the processing circuitry may beconfigured to estimate rate of ventilations applied to the patient. Insuch an example, the output device may be configured to provideinstructions to a user for administering ventilations to the patientbased on the estimated rate of ventilations.

According to another aspect of the present disclosure provided is asystem for facilitating resuscitation that comprises: a resuscitationassembly configured for use with patients weighing less than 55 lbs;processing circuitry; and an output device. The resuscitation assemblycomprises: a first electrode assembly comprising a therapy side and afirst motion sensor, the therapy side of the first electrode assemblyincluding a first conductive gel having an active area forelectrotherapy of approximately 15-80 cm²; and a second electrodeassembly comprising a therapy side and a second motion sensor, thetherapy side of the second electrode assembly including a secondconductive gel having an active area for electrotherapy of approximately15-80 cm². The processing circuitry is operatively connected to theresuscitation assembly and is configured to receive and process signalsfrom the first and second motion sensors to estimate at least one of acompression depth and rate during administration of chest compressions.The output device is for providing guidance to a user to administerchest compressions based on the estimated chest compression depth orrate.

In some examples, at least one of the first motion sensor and the secondmotion sensor may be separable from the respective first or secondelectrode assembly. The processing circuitry may be configured toidentify the resuscitation assembly as one of a pediatric or adultresuscitation assembly based on an identification signal. The processingcircuitry may be configured to determine a placement orientation of thefirst electrode assembly and the second electrode assembly on a patient.The chest compression depth may be calculated by subtracting a distancetraveled by the second motion sensor from a distance traveled by thefirst motion sensor. The first motion sensor may be configured toproduce a first signal representative of acceleration caused bycompressions and the second motion sensor is configured to produce asecond signal representative of acceleration due to movement on acompressible surface. The processing circuitry may be configured toutilize signals from the first motion sensor and the second motionsensor to determine depth of compression when an infant or neonatalpatient is squeezed from both the front and back during CPR.

The processing circuitry and the output device may be provided in anexternal defibrillator. At least one of the first electrode assembly andthe second electrode assembly may include a flexible electrode layerincluding the therapy side. The output device may be configured toprovide instructions to a user for a surface upon which the patient ispositioned to be changed based on information sensed from the first andsecond motion sensors. At least one of the first motion sensor and thesecond motion sensor may comprise an accelerometer capable of measuringacceleration in multiple directions. The processing circuitry may beconfigured to estimate a difference in orientation between the firstelectrode assembly and the second electrode assembly. The processingcircuitry may also be configured to estimate an angle relative to avertical axis of the patient at which a user is administering chestcompressions during CPR based on the signals received from the first andsecond motion sensors. The output device may be configured to provideinstructions to a user for administering chest compressions based on theestimation of orientation between the first and second electrodeassemblies.

According to another aspect of the present disclosure, provided is asystem for facilitating resuscitation that comprises a resuscitationassembly configured for use with patients weighing more than 55 lbs,processing circuitry, and an output device. The resuscitation assemblycomprises: a first electrode assembly comprising a therapy side and afirst motion sensor, the therapy side of the first electrode assemblyincluding a first conductive gel having an active area forelectrotherapy of 50-150 cm²; a second electrode assembly comprising atherapy side and a second motion sensor, the therapy side of the secondelectrode assembly including a second conductive gel having an activearea for electrotherapy of 50-150 cm². The processing circuitry isoperatively connected to the resuscitation assembly and is configured toreceive and process signals from the first and second motion sensors toestimate at least one of a compression depth and rate duringadministration of chest compressions. The output device is for providingguidance to a user to administer chest compressions based on theestimated chest compression depth or rate.

These and other features and characteristics of the present disclosure,as well as the methods of operation and functions of the relatedelements of structures and the combination of parts and economies ofmanufacture, will become more apparent upon consideration of thefollowing description and the appended claims with reference to theaccompanying drawings, all of which form a part of this specification,wherein like reference numerals designate corresponding parts in thevarious figures. It is to be expressly understood, however, that thedrawings are for the purpose of illustration and description only andare not intended as a definition of the limit of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B illustrate placement of an example of a resuscitationassembly in accordance with the present disclosure on a cardiac arrestvictim;

FIG. 1C is a perspective view of the resuscitation assembly of FIGS. 1Aand 1B;

FIGS. 2A and 2B are side views that illustrate placement of aresuscitation assembly;

FIG. 2C is a side view of an electrode assembly of the resuscitationassembly of FIG. 1B;

FIG. 3 is a perspective view of an electrode assembly of a resuscitationassembly in accordance with an embodiment;

FIG. 4 is an exploded view of the electrode assembly of theresuscitation assembly of FIG. 1B;

FIG. 5 is a perspective view of an alternative example of an electrodeassembly in accordance with the present disclosure;

FIG. 6 is a perspective view of an electrode assembly of FIG. 3 with alayer partially removed;

FIG. 7 is a perspective view of a sensor assembly for use withresuscitation assemblies in accordance with various embodiments;

FIG. 8 illustrates placement of the electrode assembly of FIG. 5 on avictim;

FIG. 9 is a perspective view of another example of an electrode assemblyin accordance with an embodiment;

FIG. 10 is a perspective view of a sensor assembly for use with theelectrode assembly of FIG. 9;

FIG. 11 illustrates placement of the electrode assembly of FIG. 9 on avictim;

FIG. 12 illustrates an alternative placement of another example of aresuscitation assembly on a victim in accordance with some embodiments;

FIG. 13A is a perspective view of a resuscitation assembly in accordancewith an embodiment;

FIG. 13B is a perspective view of a resuscitation assembly in accordancewith another embodiment;

FIG. 14 is a perspective view of a resuscitation assembly in accordancewith another embodiment;

FIG. 15 is a flow chart of an exemplary process used for determiningplacement of the electrode assemblies of the resuscitation assembly andchest compression depths in accordance with some embodiments;

FIG. 16 illustrates the two-thumb technique for accomplishing CPRcompressions on an infant utilizing a resuscitation assembly inaccordance with some embodiments;

FIG. 17 is a side schematic view of compressions being applied to apatient utilizing a resuscitation assembly in accordance with someembodiments;

FIG. 18 is a flow chart of an exemplary process used for providingfeedback to a rescuer regarding the surface upon which a patient ispositioned in accordance with some embodiments.

FIG. 19 illustrate placement of an example of a resuscitation assemblyin accordance with the present disclosure on a cardiac arrest victim;

FIGS. 20A and 20B illustrate an alternative placement of theresuscitation assembly of FIG. 19 in accordance with the presentdisclosure on a cardiac arrest victim;

FIGS. 21A and 21B illustrate placement of an example of a resuscitationassembly in accordance with the present disclosure on a cardiac arrestvictim;

FIG. 22 is a side view of the electrode assembly of the resuscitationassembly of FIG. 21B;

FIGS. 23A and 23B illustrate placement of an example of a resuscitationassembly in accordance with the present disclosure on a cardiac arrestvictim;

FIGS. 24A and 24B illustrate placement of an example of a resuscitationassembly in accordance with the present disclosure on a cardiac arrestvictim;

FIG. 24C illustrates placement of a posterior electrode assembly havingan alternative example of a lead wire than the posterior electrode ofFIG. 24B;

FIGS. 25A and 25B illustrate placement of an example of a resuscitationassembly in accordance with the present disclosure on a cardiac arrestvictim;

FIGS. 26A and 26B illustrate placement of an example of a resuscitationassembly in accordance with the present disclosure on a cardiac arrestvictim; and

FIGS. 27A and 27B illustrate placement of an example of a resuscitationassembly in accordance with the present disclosure on a cardiac arrestvictim.

DETAILED DESCRIPTION

The present disclosure relates to resuscitation assemblies and systemsthereof that may be used for a wide variety of patients in need ofresuscitation, such as for small (e.g., pediatric, infant) or large(e.g., adult) patients. In various embodiments, the resuscitationassemblies may include at least a pair of electrode assemblies, whereeach electrode assembly includes an electrode pad and a motion sensor.Though, for some embodiments, a resuscitation assembly may include asingle electrode assembly, having an electrode pad and an associatedmotion sensor, or multiple electrode assemblies, having an electrode padand an associated motion sensor.

Resuscitation assemblies and systems described herein may provide forimproved resuscitation over prior devices and methods, for example, byproviding improved accuracy, detection and/or correction in determiningresuscitation related parameters, such as chest compression depth,release velocity, angle of chest compressions, the presence of anerror-inducing surface (e.g., compressible surface under patient, suchas a soft mattress, etc.), chest compression rate and/or timing,ventilation rate, etc. Systems and resuscitation assemblies inaccordance with the present disclosure provide improved accuracy indetermining chest compression depth than previously possible, forexample, by detecting and/or correcting for errors in resuscitationparameters as a result of external sources, e.g. error-inducing surface,patient is in transport (e.g., traveling on a gurney/stretcher or withinan ambulance), etc. Accordingly, such systems may advantageously provideimproved feedback on whether chest compressions are appropriatelyapplied and/or whether the rescuer needs to correct for error from anexternal source (e.g. change the surface on which the patient is placed,reduce other motion induced error, etc.).

In certain examples, as illustrated in FIGS. 1A-1B, the resuscitationassemblies of this disclosure comprise two electrode assemblies, eachcomprising an electrode pad and one or more chest compression sensors.One electrode assembly may be placed at an anterior position (e.g., overthe sternum) of the patient and a second electrode assembly may beplaced on a posterior position (e.g., on the back, opposite the anteriorplaced electrode) of the patient, i.e., in an A-P position.Alternatively, as illustrated in FIGS. 12 and 19, a first electrodeassembly may be placed on an anterior position of the patient and asecond resuscitation electrode assembly may be placed on a side positionof the patient, i.e., in an A-A position. In such a context, it may beadvantageous to be able to track the movement of each of the electrodeassemblies while coupled to the patient. According to variousembodiments, resuscitation assemblies described herein may be intendedfor use only in the A-P position, only in the A-A position, in eitherA-A or A-P position, and/or in a different position, such as alateral-lateral position (not shown in the figures) where the electrodeassemblies are placed on each side of the patient.

As described herein, each electrode assembly placed on the patient mayincorporate one or more chest compression sensors, for example motionsensors (e.g. accelerometers, velocity sensors, ultrasonic sensors,infrared sensors, other sensors for detecting displacement). In certainexamples, the motion sensors may be single axis or multiple axisaccelerometers. Single axis accelerometers may be used to determinechest compression parameters (e.g. depth, rate, velocity, timing, etc.)by measuring and/or providing signals that assist in determiningacceleration, velocity and/or displacement. Multi-axis accelerometers,e.g. a three-axis accelerometers, may be able to provide signals thatfurther determine relative orientation of their respective electrodeassemblies by measuring parameters indicative of motion along each axis,in addition to determining chest compression parameters. The motionsensor may also include a gyroscope for determining orientation of thesensor (and, in some cases, the electrode assembly) by way of tilt orrotation. In additional examples, two or more accelerometers may bearranged orthogonally with respect to each other, to determine electrodeand/or chest acceleration in multiple orthogonal axes. Generallyspeaking, while an accelerometer senses acceleration or gravity, motionor displacement of the accelerometer can be determined through a seriesof calculations (e.g., double integration, etc.) known to those of skillin the art.

By incorporating motion sensors in both electrode assemblies,resuscitation related parameters may be more accurately determined thanwould otherwise be the case if only one electrode assembly incorporateda motion sensor. For instance, the electrode assemblies may serve asreference points for one another, based on their respective displacementand orientation. Accordingly, the manner in which the electrodeassemblies (e.g., electrode pads) are placed and/or how they moverelative to one another may inform the type of instructions output to arescuer. As an example, discussed further below, based on theirorientation and/or distance relative to one another, it can bedetermined whether the electrode assemblies are placed in an A-A or A-Pposition, or not in any typical position at all, such as alateral-lateral position where the electrode assemblies are placed oneither side of the patient. In addition, based on the pattern ofmovement of both electrode assemblies, the type of surface on which thepatient resides can be determined, the angle with respect to thevertical axis (when the patient is lying down) at which chestcompressions are being administered can also be estimated, or thedirection normal to the patient when the patient is lying down on aslanted surface.

As also provided herein, the electrode assemblies may be constructed tosuitably conform to the patient's body. For example, an electrodeassembly may comprise a sensor housing (e.g., containing one or moremotion sensors, casing, protective and/or padding material) and aflexible electrode pad, where the sensor housing is more rigid than theflexible electrode pad. The sensor housing may be coupled with theflexible electrode pad in a manner that allows the electrode pad tomaintain its flexibility, thus allowing it to conform to the patient'sbody. For example, the sensor housing may be attached to the electrodepad at a portion of the electrode pad, allowing another portion of theelectrode pad (the portion of the assembly that is used to sense ECG anddeliver the therapeutic shock) to retain its flexibility in order toconform to the patient's anatomy.

In some embodiments, the sensor housing includes padding material and/orprotective covering that surrounds the motion sensor. For example, asshown in FIGS. 2B, 3, 4 and others, the motion sensor may be integratedinto a portion of the padding (e.g., motion sensor may be containedwithin an upper padding portion which does not include the conductivetherapeutic material of the electrode pad) of the electrode assembly.Though, for certain embodiments, the sensor housing does not includepadding material. For example, as illustrated in FIGS. 7 and 10, thesensor housing may include a protective covering (e.g.,plastic/polymeric encasement), separate from a larger padding material.That is, the motion sensor may be provided as part of an electrodeassembly and coupled (e.g., wired, wirelessly) to an overallresuscitation system, associated with an appropriate electrode pad, yetis separate or is otherwise able to be positioned independently from theelectrode pad. It can also be appreciated that a sensor housing mayinclude both a protective covering (e.g., polymeric/plasticencasement/casing), within which a motion sensor is disposed, and alarger padding material, within which the protective covering is furtherdisposed.

FIGS. 1A-1C describe a resuscitation assembly of the present disclosure,comprising a pair of electrode assemblies, denoted generally asreference numerals 1A and 1B, in accordance with the present disclosurethat are placed on a patient 3. The patient 3 is shown with the twoelectrode assemblies 1A, 1B secured to the chest and back, respectively,of the patient 3 in an anterior-posterior (A-P) configuration. While theelectrode assemblies shown in FIGS. 1A and 1B are shown as beingattached to a patient in an A-P configuration, this is not to beconstrued as limiting the present disclosure as the electrode assembliesmay also be attached to the patient according to other configurations,such as in an anterior-anterior (A-A) configuration as shown in FIG. 12and discussed in greater detail hereinafter.

The resuscitation assembly of FIGS. 1A and 1B is operatively connectedto a defibrillator 5, such as a ZOLL Medical R Series or X SeriesMonitor Defibrillator, which can operate as an AED, a semi-automaticdefibrillator (SAD), and/or a manual defibrillator with a monitor, andcan also be used for cardioverting and pacing (where electrical pulsesare delivered through the patient's chest according to a vector at leastpartially determined by placement of the pads, so as to stimulate theheart to contract), through cables 7. However, this is not to beconstrued as limiting the present disclosure as the resuscitationassembly of the present disclosure may be used with any suitabledefibrillator system. The defibrillator 5 is operable to generate adefibrillating shock and deliver that shock to the patient through theelectrode assemblies 1A, 1B. In one example, the defibrillator 5 caninclude an ECG monitor and display for analyzing the ECG signalsobtained through the electrode pad and displaying the ECG waveform to auser. The display can also provide the user with feedback regardingchest compressions as disclosed in U.S. patent Ser. No. 14/499,617,entitled “Defibrillator Display,” assigned to the assignee of thepresent application, and which is hereby incorporated by reference inits entirety.

With reference to FIGS. 1A-4, the resuscitation assembly includes two(or more) electrode assemblies that each may include a flexibleelectrode pad 9 having a therapy side 11 configured to be coupled to thepatient 3, a sensor housing 13 attached to a side 15 of the electrodepad 9 opposite the therapy side 11 at an attachment region 17, and amotion sensor 19 enclosed within the sensor housing 13. In variousembodiments, it may be preferable for a motion sensor to be embeddedwithin a sensor housing so that the sensor (and associated casing) isprotected from being damaged and is securely held by the electrodeassembly so as not to be subject to undesirable movement within thehousing. While not expressly shown in the figures, the sensor housing 13may include both a padding material and an optional protective casingfor the motion sensor 19.

While the motion sensor 19 is illustrated in FIGS. 3-4 as beingcompletely enclosed within the padding material of sensor housing 13,this is not to be construed as limiting the present disclosure as themotion sensor 19 (and its respective encasement) may be only partiallyenclosed within the padding of the sensor housing 13. For example,motion sensor 19 and encasement may be at least partially exposed, suchas in the embodiment shown in FIG. 6. In such examples, the motionsensor and encasement may be constructed to be removable, repositionedand/or replaced.

As provided herein, and shown in FIG. 2C, the flexible electrode pad 9may be attached to a comparatively more rigid sensor housing 13 at anattachment region 17 which spans only a fraction of the area of contactthere between. That is, the area of attachment between the flexibleelectrode pad 9 and the sensor housing 13 may extend only partiallyacross the surface of the electrode pad 9, allowing the portion of theelectrode pad 9 that remains unattached to remain flexible and conformto the patient's body. Accordingly, by allowing the portion of theelectrode pad 9 that remains unattached to the sensor housing 13 todeflect or otherwise flex back and forth, the sensor housing 13 does notundesirably force the electrode pad 9 to peel away from the patient'sbody.

The electrode pad 9 and sensor housing 13 may be attached by anysuitable method, for example, at the point of attachment, the electrodepad and the housing may be formed of the same material (e.g., foampadding), mechanically coupled (e.g., interlocking), stapled, sutured,stitched, non-adhesively coupled, adhesively coupled, or otherwiseadhered. For example, as shown in FIG. 2C, the sensor housing 13 and theelectrode pad 9 are directly attached to one another. Accordingly,particularly for small (pediatric, undersized) patients or thosesuffering from conditions (e.g. kyphosis) that may warrant such aconfiguration, the flexible electrode pad 9 may be better suited toconform to the surface contours of the patient's body than may be thecase if the electrode pad 9 and sensor housing 13 are attached along theentire surface of contact there between (e.g., having a completely flushattachment between the non-therapy side of the electrode pad and thepadding material of the sensor housing). Otherwise, as discussed above,without such a construction, or similar arrangement thereof, there maybe a greater tendency for the entire assembly to lift off from thepatient's body. Though, as described further herein, it can beappreciated that for some embodiments, the electrode pad and motionsensor (along with sensor housing and/or sensor casing) are not requiredto be directly attached to one another.

The flexible electrode pad 9 may be any type of electrode suitable foruse in defibrillation, and generally includes a conductor, such as tin,silver, AgCl or any other suitable conductive material, provided at thetherapy side 11; a conductive electrolyte gel (e.g., solid, adhesivepolymer), such as a hydrogel; and lead wires to connect the conductor tothe cable 7. In various illustrative embodiments, for pediatricelectrodes, the gel has an active (electrotherapy) area of at leastapproximately 15 cm² (e.g., approximately 15-30 cm², approximately 15-40cm², approximately 15-50 cm², approximately 15-60 cm², approximately15-70 cm², approximately 15-80 cm², approximately 15-90 cm²,approximately 15-100 cm², approximately 20-40 cm², approximately 20-50cm², approximately 20-60 cm², approximately 20-70 cm², 3 approximately0-50 cm², approximately 30-60 cm², approximately 30-70 cm²) for eachelectrode with a combined total area for both electrodes of at leastapproximately 45 cm² (e.g., approximately 45-60 cm², approximately 45-70cm², approximately 45-80 cm², approximately 45-90 cm², approximately45-100 cm², approximately 45-120 cm², approximately 45-150 cm²). As anexample, an anterior pediatric electrode may have a conductive geltherapy area of at least approximately 15 cm² (e.g., approximately 5.5″max length, approximately 4.5″ max width), and a posterior pediatricelectrode may have a conductive gel therapy area of at leastapproximately 15 cm² (e.g., approximately 5.75″ max length,approximately 3.5″ max width). As another example, an anterior pediatricelectrode may have a conductive gel therapy area of approximately 40 cm²(e.g., approximately 32 cm length, approximately 27 cm width), and aposterior pediatric electrode may have a conductive gel therapy area ofapproximately 50 cm² (e.g., approximately 36 cm length, approximately 22cm width). In other illustrative embodiments, for adult electrodes, thegel has an active (electrotherapy) area of at least approximately 50 cm²(e.g., approximately 50-80 cm², approximately 50-90 cm², approximately50-100 cm², 50-110 cm², approximately 50-120 cm², approximately 50-130cm², approximately 50-140 cm², approximately 50-150 cm²) for eachelectrode with a combined total area of at least approximately 150 cm²(e.g., approximately 150-200 cm², approximately 150-250 cm²,approximately 150-300 cm²). As an example, an anterior adult electrodemay have a conductive gel therapy area of approximately 80 cm², and aposterior adult electrode may have a conductive gel therapy area ofapproximately 115 cm². The above described dimensions and measurementsqualified by the term approximately include the specified dimensionand/or measurement taking into account limits of measurement and typicalsources of error.

The flexible electrode pads 9 of electrode assemblies 1A, 1B may besimilar in their layered construction, although as illustrated, thelateral shapes of the pads may vary depending on where the pads are tobe placed on the patient. For instance, the electrode pad ofresuscitation electrode assembly 1A is shown to have rounded edges,providing for relatively easy placement on the chest area of a patient'sthorax, while the electrode pad of electrode assembly 1B is shown to berectangular, providing for more intuitive alignment with the spine onthe back area of the patient's thorax than would otherwise be the casefor other shapes. In addition, in various embodiments, electrodeassemblies described herein may be made from radiolucent and/orradiotransparent materials, and thus, translucent or transparent toX-rays. Accordingly, the electrode assemblies would not interfere withstandard imaging techniques. For instance, at least one of the flexibleelectrode pad 9, the therapy side 11, and the sensor housing 13 may bemanufactured from radiolucent and/or radiotransparent materials. In oneexample, the flexible electrode pad 9, the therapy side 11, and thesensor housing 13 are all manufactured from radiolucent and/orradiotransparent materials. In general, radiolucent electrode pads mayinclude materials that include both radiotransparent and radiopaquematerials, where the main body of the electrode pad is transparent toX-rays, but the materials of the sensor (e.g., electronics, cableconnections, etc.) are not transparent to X-rays. As a result, when thepatient is subject to X-rays or other techniques of imaging, theelectrode assemblies, or portions thereof (excluding materials that arenot radiotransparent), adhered or otherwise applied on to the patient'sbody would not appear in the image, and so the internals of the patientmay be suitably viewed.

The flexible electrode pads 9 each may include an insulating base layer21 (e.g., flexible foam base layer) and a flexible conductor 23 providedon the therapy side 11 thereof (see FIG. 3, for example). The insulatingbase layer 21 is composed of a layer of flexible, soft closed cell-typepolymer foam such as, but not limited to, medical grade polyethylene orother suitable material(s). The material of base layer 21 may be of ahigh enough density sufficient to provide a barrier to liquid or aqueousgel, so that the conductive gel is held substantially in place on thetherapy side of the electrode pad. The material of the base layer 21 mayalso be flexible and/or compressible in nature so as to conformcomfortably to the surface contours of a patient's anatomy when theelectrodes are affixed to the patient, without irritation or lifting offfrom the body.

The dimensions of the base layer 21 may be determined based onphysiological considerations for both transcutaneous pacing anddefibrillation. The area of the conductor 23 of the flexible electrodepads 9, which may be smaller than the corresponding base layers 21, maybe constructed to extend laterally past the heart so that the entireheart is in effect “covered” by a defibrillation pulse. In addition, thebase layer 21 dimensions may be chosen to provide some amount of areasurrounding the conductor 23 for suitable adhesion to a patient'sanatomy. For example, the area surrounding the conductor 23 can becoated with a hypoallergenic medical grade acrylic adhesive designed foruse on human skin. This adhesive provides the mechanism for temporarilyaffixing the flexible electrode pads in position on a patient's anatomy.Using such an adhesive, no additional adhesive or additional manualforce may be required to maintain the electrodes in position duringdelivery of electrical signals to a patient. Further details of theflexible electrode pads can be found in U.S. Pat. No. 5,330,526,entitled “Combined defibrillation and pacing electrode,” which isassigned to the assignee of the present application and is herebyincorporated by reference in its entirety.

The sensor housing 13 may include one or more layers of compressible,padded material which, as discussed above, may be attached to the side15 of the flexible electrode pad 9 opposite the therapy side 11 at anattachment region 17 such that the sensor housing 13 is not connectedacross the entire surface of the flexible electrode pad 9. As anexample, shown in FIGS. 2B and 4, the sensor housing 13 may include asingle layer of compressible, padded material which is thicker than theflexible electrode pad 9 such that the sensor housing 13 exhibits agreater degree of rigidity as compared to the electrode pad 9. In thiscase, the padding portion of the sensor housing 13 may be substantiallythicker than that of the electrode pad 9 and, hence, the padding portionof the sensor housing 13 may be more rigid than the electrode pad 9.

In another example, and as shown in FIG. 3, the sensor housing 13 mayinclude a plurality of layers of compressible, padded material. Theselayers may be laminated to each other to form the sensor housing 13 andadhered to the flexible electrode pad 9 at the attachment region 17. Insome embodiments, the layers may be adhesively bonded, integrally formedor otherwise attached to each other, and further attached to theelectrode pad 9 at the attachment region 17. In various embodiments, thecompressible, padded material of the sensor housing 13 has a rigiditythat is greater than that of the flexible electrode pad 9, yet may stillbe compressible as a padding material. Non-limiting examples of suchmaterial include medical grade polyethylene, foam, flexible polymericmaterial, gel, or other suitable materials.

Embodiments of the present disclosure allow for electrode assemblieswhere a motion sensor 19 is positioned directly over the flexibleconductor 23 of the electrode pad 9. This may be particularlyadvantageous for pediatric or neo-natal resuscitation assemblies, whichare relatively small compared to their adult counterparts due to thelimited amount of surface space available. By way of context, conductivematerials such as those incorporated in electrode pads 9 discussedherein may be prone to wear and/or damage when subject to repeatedcompressive loading applied directly thereto. Such wear or damage mayinclude, for example, roughened surfaces, jagged edges,dislodged/displaced material, etc., which may result in the developmentof regions having uneven electrical resistance. When certain regions ofthe conductive material are more resistive than others, there may be agreater tendency for heat to be undesirably localized (e.g., “hotspots”) during defibrillation discharge. Such thermal localization mayresult in pain, burns, or other issues to the patient. However, when thecompressive forces applied during chest compressions are welldistributed, for example, directed at a location substantially away fromthe conductive material or are otherwise reduced/minimized (e.g., viapadded, cushioned structure), it is less likely for the conductivematerial to develop wear or damage, hence, reducing the occurrence ofhot spots along the patient's body during discharge. The construction ofelectrode assemblies provided herein allow for such compressive forcesto be distributed in such a manner that minimizes or otherwise reducesthe likelihood that the conductive material be undesirably damaged.

With reference to FIGS. 1A and 2A, the sensor housing 13 of electrodeassembly 1A may be configured to enable a rescuer to apply chestcompressions thereto. In this case, the sensor of resuscitationelectrode assembly 1A is offset from the center of the conductivematerial of the electrode pad 9 so that the conductive material is morelikely to remain undamaged during chest compressions. Also, the sensormay be positioned a suitable distance away from the electricalconnection to the electrode pad, so that there is a reduced chance forthe connection itself from being damaged during compressions. Inaddition, an upper surface 24 of the sensor housing 13 of electrodeassembly 1A can include graphics, such as a cross-hair indicia 25, thatserves to guide a user to properly place the sensor housing 13 at asuitable anterior position over the sternum of the patient 3.

In additional examples, the electrode assembly 1B, illustrated in FIGS.1B and 2B, may be configured such that the motion sensor 19 is locatedover a central portion of the conductive material. Accordingly, thesensor housing 13 of electrode assembly 1B is configured to distributecompressive forces indicative of CPR substantially evenly across theconductor 23 of the flexible electrode pad 9. That is, for the posteriorpositioned electrode assembly 1B, even though compressive forces aretransferred between the conductive material of the electrode pad 9 andthe (comparatively rigid) motion sensor 19, the potentially damagingeffect(s) of such forces may be reduced, for example, due to enhancedcushioning provided by the sensor housing 13. For example, the thicknessof the padded material of the sensor housing 13 may provide sufficientcushioning for the conductor 23 to remain undamaged during chestcompressions.

With reference to FIG. 4, the motion sensor 19 may be enclosed withinthe compressible padded layer(s) of the sensor housing 13. The motionsensor 19 may be a three-axis accelerometer or any other suitable motionsensor. As shown in FIG. 4, the motion sensor 19 may be located over acentral region of the conductor 23 of the flexible electrode pad 9. Themotion sensor 19 may have any suitable shape. For instance, as shown inFIG. 4, the motion sensor 19 may have a square or rectangular shape.This shape may be the shape of the motion sensor 19 itself or formed bya casing or other covering, such as an encapsulation or overmolding asdiscussed below. Alternatively, as shown in FIGS. 7 and 10, the motionsensor may have a circular shape. Other shapes and sizes may bepossible, for example, the motion sensor may exhibit shapes that arepolygonal, oval, similar to a credit card or coin, amongst others. Asdiscussed above, the sensor housing 13 may be structured so as todistribute compressive forces substantially evenly across the conductor23 during CPR chest compressions. In further embodiments, the motionsensor 19 may be located at a periphery of the conductor 23 of theflexible electrode pad 9 as shown for example in FIGS. 6 and 9 discussedin greater detail hereinafter.

In order to further protect the motion sensor 19 from the environment,such as moisture, humidity, defibrillation shocks, etc., it may beencapsulated or overmolded with a polymeric material, such as a moldablepolyamide, to form a suitable sensor casing. The polymeric material maybe suitable to provide long term protection from extreme temperature andmoisture condition, as the overall assembly may be stored for years at atime. A non-limiting example of such a material is MacromeltOM652/Technomelt PA 752 provided by Henkel Corporation. Theencapsulation material may be directly overmolded onto the motion sensor19 or may form a protective casing in which the motion sensor 19 ispositioned. The material may further be flexible, textured and/orslightly compressible, to provide enhanced comfort for the user, yetalso sufficiently rigid or high enough in strength so as to provideprotection for the sensor itself.

As discussed herein, the casing for the sensor may provide not only aprotective covering for the sensor itself, but also may provide a sourceof traction for the provider of chest compressions, particularly wherethere may be a tendency for the rescuer's hands to slip on bare skin,for example, covered by blood, fluids, sweat, or other lubricatingmaterial. Any suitable material(s) and construction may be used. Forexample, the sensor casing may include multiple materials and/or layers,such as a rigid plastic for an inner portion that encapsulates thesensor itself to protect the electronics (e.g., accelerometer circuit),and a softer material (e.g., silicone, rubber, elastomer, polyurethane,neoprene, gel, polymeric material) provided as an over mold or thincoating for added comfort.

The material(s) of the casing may exhibit an appropriate level ofhardness. In certain embodiments, as noted above, the casing may includea relatively rigid inner protective cover and a softer exteriorcovering. For example, relatively softer material(s) of the casing forproviding added comfort for the user may have a shore A durometer ofbetween approximately 40 and approximately 90, between approximately 40and approximately 60, between approximately 50 and approximately 80,between approximately 60 and approximately 70, or a shore A durometeroutside of the above noted ranges. Relatively hard material(s) of thecasing for providing added protection for the sensor circuitry may havea shore D durometer of between approximately 20 and approximately 80,between approximately 30 and approximately 60, between approximately 30and approximately 50, or a shore D durometer outside of these ranges. Insome embodiments, as noted above, the sensor casing may include arelatively hard material that is coated with a thin softer material orlaminate.

By providing a suitable motion sensor in both the anteriorly positionedelectrode assembly 1A and the posteriorly positioned electrode assembly1B, the signals obtained therefrom can be processed by control circuitryprovided in the defibrillator 5 to provide information that enhancesoverall resuscitation care to the patient. For example, data from bothmotion sensors may be processed to determine more accurate compressiondepth, particularly when compressions are performed on a compressiblesurface and/or when, on an infant, a rescuer wraps his/her hands aroundthe infant's chest and squeezes from both the front and back, as will bediscussed in greater detail hereinafter.

As one mechanism to ensure proper placement of the electrode assemblies1A, 1B of the resuscitation assembly onto the patient's anatomy, one orboth of the electrode assemblies, or a substrate connected to theassemblies, may be provided with pictograms, diagrams, or printedinstructions 27 describing the correct position for the electrodeassemblies 1A, 1B. For example, pictograms, diagrams, or printedinstructions may be provided on an upper surface 24 of the sensorhousing 13 or the side 15 of the flexible electrode pad 9 opposite thetherapy side 11. In addition, signals from the motion sensors 19 may beutilized by the control circuitry of the defibrillator 5 to prompt theuser in the manner in which the resuscitation assemblies, including theelectrode assemblies 1A, 1B, should be placed as discussed in U.S.patent application Ser. No. 15/083,044, entitled “ECG and DefibrillatorElectrode Detection and Tracking System and Method,” filed on Mar. 28,2016, which is hereby incorporated by reference in its entirety.

As discussed herein, the sensor housing 13 may be constructed such thatit is generally more rigid than the flexible electrode pad 9.Accordingly, as shown in FIGS. 2A, 2B and 2C, at least a portion 29 ofthe flexible electrode pad 9 is constructed and arranged to retain itsflexibility throughout the portion not corresponding to the attachmentregion 17 such that the electrode pad 9 substantially conforms to thepatient's anatomy when coupled to the patient 3. As shown in FIG. 2A,the attachment region 17 is provided along a portion of the upper leftperiphery of the flexible electrode pad 9 (when viewing the assemblyfrom the top). With reference to FIG. 2B, the attachment region 17 canbe located at a central region of the flexible electrode pad 9 such thatthe sensor housing 13 is free from attachment with a periphery of theflexible electrode pad 9. In some embodiments, the resuscitationassembly shown in FIGS. 2A-2C is intended for use in the A-P position,and may particularly beneficial for use with pediatric patients.

It can be appreciated that various alternative attachment regions 17 maybe utilized such as, but not limited to attachment at a central upperregion and/or a central lower region of the assembly. In eachconfiguration, since the more rigid sensor housing 13 is only connectedat the attachment region 17 and not across the entire surface of theflexible electrode pad 9, forces delaminating or otherwise pulling theflexible electrode pad 9 away from the patient's anatomy due to theconnection between the sensor housing 13 and the flexible electrode pad9 are reduced and at least a portion of the flexible electrode pad 9 iscapable of flexing away from the sensor housing 13. This allows theflexible electrode pad 9 to better follow contours of the patient'sanatomy so as to be suitably adherent thereto while remaining attachedto the sensor housing 13 than would otherwise be the case if theflexible electrode pad were attached completely flush to the sensorhousing. The flexible electrode pad is also able to provide relativelyuniform electrical contact between the electrode and the patient, so asto maintain a sufficiently large active area of contact for a suitableamount of electrotherapeutic (e.g., defibrillation) energy to bedelivered. Otherwise, if the electrode pad is not flexible enough toconform to the patient's anatomy, the reduced surface area may lead toissues, such as burning, skin damage, and/or improper electric fieldlines between electrodes, giving rise to improper delivery ofelectrotherapy.

It should be understood that embodiments of a resuscitation assembly mayemploy other arrangements. With reference to FIGS. 5-8, an alternativeexample of an electrode assembly 51 of a resuscitation assembly isillustrated. In this example the resuscitation assembly comprises one ormore electrode assemblies. FIGS. 5-8 illustrate how one of the electrodeassemblies may be constructed. For example, an electrode assembly 51 maybe configured to be attached at a posterior position on a patient'sback. The electrode assembly 51 includes a flexible electrode pad 53having a therapy side 55 configured to be coupled to the patient 3, asensor housing 57 attached to a side of the electrode pad 53 oppositethe therapy side 55, and a motion sensor 59 (with associated casing)enclosed within the sensor housing 57.

The flexible electrode pad 53 may be any type of electrode suitable foruse in defibrillation, and generally includes a conductor, such as tin,silver, AgCl or any other suitable conductive material, provided at thetherapy side 55; an electrolyte, such as a hydrogel; and lead wires toconnect the conductor to a cable as discussed herein.

For various embodiments, and as shown in this figure, the sensor housing57 may include a plurality of layers of compressible, padded materialattached to the side of the flexible electrode pad 53 opposite thetherapy side 55 at an attachment region (not expressly shown) such thatthe sensor housing 57 and the flexible electrode pad 53 are notconnected across the entire surface of contact. While not shown in FIGS.6-8, the sensor housing 57 may be attached to the flexible electrode pad53 similar to the manner in which the sensor housing 13 of electrodeassembly 1B is attached to the flexible electrode 9 as shown in FIG. 2B.For instance, the attachment region may be located at a central regionof the flexible electrode pad 53 such that the flexible electrode pad 53deflects or otherwise flexes from the sensor housing 57 at a locationaway from the attachment region, peripheral to the central region,whereby the electrode pad 53 substantially conforms to the patient'sanatomy when coupled to the patient 3.

The electrode assembly 51 may be structured according to any suitableconfiguration. For example, certain portions of the electrode assembly51 may be shaped to accommodate and suitably conform to various parts ofthe anatomy upon placement thereon. For some embodiments, the sensorhousing 57 and/or electrode pad 53 may be constructed such that theassembly comprises columns of differing thickness, resulting in betterconformance of the assembly to the patient's anatomy. For example, asshown in FIGS. 5 and 8, the sensor housing 57 may be patterned in threecolumns 58 a, 58 b, and 58 c. As illustrated, the first column 58 a andthe third column 58 c may exhibit a similar thickness, whereas thesecond column 58 b may have a smaller thickness so that the assembly 51may be more geometrically appropriate to accommodate space occupied bythe spine of the patient 3. Alternatively, for certain embodiments whereit may be preferred for the sensor not to be placed over the spine,columns of varying thicknesses are not necessary. For example, an imageof the spine may be provided on the posterior assembly (e.g., sensorhousing or electrode pad) so that the assembly is placed in a mannerthat avoids placement of the sensor directly on or over the spine.

In some embodiments, the sensor housing 57 may include multiple layerslaminated to each other to form the overall sensor housing. These layersmay be further laminated or otherwise attached to the flexible electrodepad 53 at the attachment region. Alternatively, the layers may beadhesively bonded to each other and to the electrode pad 53 at theattachment region. The layers may be attached to one another by anyother suitable method, such as by one or more fasteners (e.g., stitches,sutures, staples, etc.), or portions of the layers may be integrallyformed. It can be appreciated that a layered configuration is notrequired, as covering materials may be shaped, molded, machined,pressed, modified or otherwise produced in any suitable manner.

The compressible, padded material of the sensor housing 57 may be morerigid than the flexible electrode pad 53, yet may still be compressiblein nature. With specific reference to FIG. 6, at least one of the layersof the sensor housing 57 may have a cut-out region 61 or other recesshaving a substantially similar size and shape as the motion sensor 59and configured to receive the motion sensor 59 therein. Accordingly, themotion sensor 59 may be embedded in only a small portion of thecompressible, padded layers of the sensor housing 57, laterally offsetfrom the conductor of the electrode pad 53. This allows forces fromcompressions to be distributed evenly across the sensor housing and maysubstantially prevent the motion sensor from damaging the electrode pad53.

As noted herein, resuscitation assemblies described herein may be usedwith electrode assemblies thereof placed in the A-P position, the A-Aposition, or both, or in another position (e.g., lateral-lateralposition). Resuscitation assemblies may be configured to perform anumber of functions, including for example, defibrillation (e.g., handsfree defibrillation energy according to energy levels set by a suitabledefibrillator), ECG monitoring (e.g., for at least 24 hours),noninvasive temporary pacing (e.g., 1-8 hours of hands free noninvasivepacing energy, at approximately 75 mA/150 ppm or approximately 140mA/180 ppm), transmitting chest compression data to a medical treatmentapparatus (e.g., defibrillator, monitor, CPR system), code readinessself testing, expiration dating, having at least a 24 month shelf life.With respect to code readiness self testing, the electrodes of theresuscitation assembly may be pre-connected to a defibrillator (e.g.,hospital defibrillator such as the R SERIES defibrillator provided byZOLL Medical) so that the assembly is ready for use at any time. Duringthe code readiness self testing, the defibrillator may automaticallytest for the presence of correct cables and electrodes, and verify thetype, condition and/or expiration date of the electrode(s), withoutrequiring the electrodes to be disconnected. For the electrodeassemblies, according to IEC 60601-2-4 cls.201.108.1.1, the AC smallsignal impedance of the electrodes is 3 kOhms or less at 10 Hz, and 5Ohms or less at 30 kHz, and the AC large signal impedance is 3 Ohms orless at a 200 J biphasic defibrillation. According to IEC 60601-2-4cls.201.108.1.4, the defibrillation recovery offset is 750 mV or lessfollowing a 200 J biphasic defibrillation at 4 and 60 seconds, andaccording to IEC 60601-2-4 cls.201.108.1.6, the DC offset voltage is 100mV or less following a 200 J biphasic defibrillation.

In certain embodiments, the resuscitation assemblies may be single usedisposable and used on certain types of patients. Such patients withwhich the resuscitation assemblies are intended for use may includepediatric patients 0-8 years in age and less than 55 lbs (25 kg), adultpatients greater than 8 years old and more than 55 lbs, or both types ofpatients. Motion sensors (anterior or posterior) associated with theresuscitation assemblies may be constructed to withstand at least 150lbs of compression force or more applied directly thereto, and at least200 compressions per minute. Such motion sensors may further be able towithstand the weight of a patient's body, in addition to the compressionforce discussed above.

The resuscitation assemblies may also include one or more componentsthat allow for a medical system to identify whether the resuscitationassembly is configured for pediatric resuscitation or adultresuscitation, or whether the resuscitation assembly has one or moremotion sensor inputs (e.g., a single sensor or multiple sensors). Insome cases, the resuscitation assembly may include a memory chip foridentifying the type of electrode assemblies, resistor (e.g.,approximately 2.9 kOhm patient identification resistor for pediatricelectrode assemblies, approximately 1.3 kOhm patient identificationresistor for adult electrode assemblies), or other suitableidentification component that is analyzed and from which anidentification signal may be transmitted. This identification signal mayprovide information for the system to determine what type ofresuscitation assembly is being used. As an example, a resuscitationassembly in accordance with the present disclosure may be connected to adefibrillator or monitor, and the system, using associated processingcircuitry, may analyze and/or receive an identification signal based onthe identification component of the resuscitation assembly. Where theidentification component is a resistor, the system may run a currentthrough the resistor, and based on the resulting voltage, the type ofresuscitation assembly may be identified. Alternatively, where theidentification component is a memory chip, the system may read whetherthe resuscitation assembly is pediatric or adult based on the contentsof the memory.

Once the system and associated processing circuitry determines the typeof resuscitation assembly that is connected, variousresuscitation-related features of the system are adjusted accordingly tosuit the therapy, such as electrotherapy, CPR parameters, user interfacedisplay, shock analysis, and/or other aspects of resuscitative therapy.For instance, if the system detects that a pediatric assembly is in use,the system may set the defibrillation energy level to be lower than ifthe system detected an adult assembly. Alternatively, depending onwhether a pediatric or adult resuscitation assembly is detected, theuser interface for providing CPR feedback may be altered. For example,when detecting that an adult assembly has been connected, the userinterface may provide estimated chest compression depth and rate valuesfor the rescuer, and also provide instructions for the rescuer to applychest compressions within a certain range of depth (e.g., 2.0-2.4inches) and rate (e.g., 100-120 cpm), according to current clinicalguidelines. However, when detecting that a pediatric assembly has beenconnected, the user interface may provide only estimated chestcompression depth and rate values, without instructing the rescuer onthe proper application of chest compressions, for example allowing atrained rescuer to administer chest compressions to the patient withoutinstructions. Further, the shock analysis algorithm applied may differdepending on whether the system detects a pediatric or adultresuscitation assembly. For instance, the pediatric shock analysisalgorithm can be calibrated to analyze a child's ECG signal rather thanan adult's EGC signal such that the defibrillator can make a moreaccurate determination of whether a shock should be delivered to thepediatric patient. In general, the defibrillator can measure the ECGbaseline content, QRS rate, width and variability, amplitude, andtemporal regularity and determine whether a shockable rhythm exists. Forthe pediatric patient, one or more of the measured values can bedifferent for a shockable rhythm than for the adult patient.

With specific reference to FIG. 7, the motion sensor 59 which, in somecases, may be embodied as a three-axis accelerometer, is mounted on aprinted circuit board 63 and encapsulated within an appropriate casing65, provided as a protective covering or encasement. As noted above,such a casing may provide the motion sensor 59 with a suitable amount ofprotection, for example, from electrical discharge and/or environmentalfactors (e.g., moisture, humidity, temperature, heat). The casing 65 mayinclude any suitable material, such as a polymeric/plastic material. Thecasing 65 is then positioned within cut-out region 61 such that a leadwire 67 extends out of the plurality of compressible, padded layers ofthe sensor casing 57. The lead wire 67 is configured to transmit thesignal from the motion sensor 59 to the control circuitry of thedefibrillator 5. The lead wire 67 may include a cable having anysuitable cross-sectional shape, and in some cases, may be round or flat.In some examples, the lead wire 67 is substantially flat (e.g., flatribbon cable) because the use of flat wires may provide a greater levelof comfort for the rescuer and patient while compressions are performedover the wire than would otherwise be the case. For instance, duringchest compressions, a round or comparably shaped lead wire may have atendency to undesirably impinge on or otherwise protrude into therescuer and/or the patient, whereas a relatively flat lead wire may beless likely to protrude into or even be noticeable to the rescuer and/orpatient. As shown, a protective covering portion of the casing 65 mayhave a shape that is substantially similar to that of the motion sensoritself, for example, to limit the overall amount of bulk around themotion sensor as well as provide for an enhanced maneuverabilitythereof.

FIGS. 9-11, illustrate another example of an electrode assembly forinclusion in the resuscitation assemblies of the present disclosure.This exemplary electrode assembly, generally denoted as referencenumeral 91, is configured to be attached posteriorly to a patient's back(see FIG. 11). The electrode assembly 91 may include a flexibleelectrode pad 93 having a therapy side 95 configured to be coupled tothe patient 3 and substantially conform to the patient's anatomy. Thetherapy side 95 includes conductive material 97, facing toward the bodyof the patient 3, adapted to provide therapeutic treatment to thepatient.

In various embodiments, the sensor casing 99 may be coupled to theelectrode pad 93 such that a projected contact area between the sensorcasing 99 and the electrode pad 93 is relatively small, such as betweenapproximately 1-100 cm². As a result, the more rigid sensor casing 99 issmall enough so that the upward force from the casing 99 is insufficientto cause delamination of the electrode pad 93 from the patient's body.In one example, the projected contact area between the sensor casing 99and the electrode pad 93 (or simply the projected area of the sensorcasing itself) is less than about 100 cm², less than about 80 cm², lessthan about 50 cm², less than about 30 cm², less than about 20 cm², lessthan about 10 cm², or less than about 5 cm². In some embodiments, thesensor casing 99 is roughly the size of a nickel. In an embodiment, thesensor casing may be approximately or less than 1.0 inch×1.0inch×0.25-0.30 inches in size. In further embodiments, the casing mayhave a projected area of approximately 0.1-4.0 inch² (e.g., 1.0-2.0 inchlength, 1.0-2.0 inch width) and approximately 0.01-0.30 inches inheight. Or, with the development of progressively smaller motion sensors(i.e., smaller chip sets), the sensor casing 99 may be as small as anencapsulating wire housing. Accordingly, the sensor casing 99 isembedded in only a small portion of the flexible electrode pad 93,thereby allowing the remaining portions of the flexible electrode pad 93to have more flexibility in adhering to the patient 3. That is, byincorporating a relatively small sensor casing 99 encapsulating anappropriately sized motion sensor 101, the likelihood that the electrodepad 93 lifts off from the patient 3 is reduced. In some embodiments, theouter surface of the sensor casing may include an appropriate texture orsuitable material (e.g., molded rigid, semi-rigid, polymeric materialwith texturing, ridges, etc.) to prevent slippage of the rescuer's handsduring compressions as well as provide an enhanced level of comfort forthe rescuer and the patient. That is, while the casing may provideprotection for the motion sensor, it is not a requirement for the casingto be rigid. For example, the casing may provide a texture that isnon-rigid and soft to the touch for the user/patient as an added degreeof comfort.

As shown, the motion sensor 101 is at least partially enclosed withinthe sensor casing 99. The motion sensor 101 may be configured to bepositioned over a periphery of the conductive material 97 such that itis offset from the patient's spine. In one example, the sensor casing 99is formed by encapsulating the motion sensor 101 in an appropriatepolymeric material. A lead wire 103, operatively connected to the motionsensor 101, extends from the sensor casing 99 and is configured totransmit the signal from the motion sensor 101 to the control circuitryof the defibrillator 5.

As discussed herein, the sensor casing 99 and motion sensor 101 may beprovided within a pouch or receptacle of the respective electrode pad towhich they are associated. In some embodiments, while the sensor casingand motion sensor may initially be contained within a portion of theelectrode pad (e.g., a housing, recess or receptacle thereof), thesensor casing and motion sensor may be removable therefrom, so that therescuer can place the sensor casing and motion sensor at any suitablelocation. For instance, it may be desirable for the sensor to be placedat a location away from the electrode pad (e.g., to avoid wounds,provide more accurate CPR measurements) and so the rescuer may have theability to easily access the sensor for subsequent placement. Or, it maybe desirable for only the sensor to be employed, without the electrodepad, hence, it would be beneficial for the rescuer to have theflexibility to take the sensor from the electrode pad and place thesensor where needed. In some cases, it may be desirable for the sensorto be removed from the electrode pad and placed on the surface (e.g.,backboard, mattress, gurney) on which the patient resides.

Traditionally, for instances in which the sensor is part of an electrodeassembly (e.g., attached or otherwise coupled with an electrode pad),the system may require for there to be an indication that the electrodepad is applied to the patient before signals from the sensor aremeasured. As an example, an impedance measurement falling within asuitable range or achieving a particular threshold may be an indicationfor confirming that the electrode pads are appropriately applied to thepatient. However, in situations where the electrode pad is not used, thesystem may not require that impedance (or another indication of padplacement) be a prerequisite for collecting signals from the sensor. Forinstance, a patient having a surgical dressing on the chest may limitthe space available for electrode pad placement, and so it may bepreferable for a sensor to be applied to the patient's chest, separatefrom the pad. In such cases, where the electrode pad is not required,ECG may be monitored via other sources (e.g., 3 lead ECG on hospitalmonitor). Accordingly, the system may include a suitable mechanism fordisabling the need for patient impedance to be measured in order forsignals to be transmitted and processed from the sensor. For example,the medical treatment apparatus (e.g., defibrillator, monitor) withwhich the sensor is in communication may have an input (e.g., switch,button, software configuration) with which a user may indicate thatsignals from the sensor(s) are to be processed, without first requiringother parameters, such as a suitable measurement of patient impedance,to confirm that the pad and/or sensor(s) are correctly placed.

Alternatively, for some embodiments, such as for neonatal resuscitation,it may be preferable for the electrode assemblies of the resuscitationassembly to exhibit a relatively low profile. For example, when treatingan infant, the rescuer may wrap his/her hands around the infant's chestand squeeze from both the front and back (i.e., using the two-thumbtechnique as discussed further below). Hence, the electrode assembliesof the resuscitation assembly may be thin enough for there to be enoughspace allowing the hands to wrap sufficiently around the infant's body.Less padding may also be required for neo-natal resuscitation becauseless force is generally applied to infants in comparison topediatric/adult compressions. In some embodiments, the resuscitationassemblies may have a thickness of less than approximately 30 mm (e.g.,approximately 1-30 mm, approximately 5-30 mm), less than approximately25 mm, less than approximately 20 mm (e.g., approximately 1-20 mm,approximately 5-20 mm), less than approximately 15 mm, less thanapproximately 10 mm, less than approximately 5 mm, less thanapproximately 2 mm, less than approximately 1 mm, or any other suitablerange of thickness.

As described further herein, it can be appreciated that for someembodiments, the motions sensor associated with a particular electrodeassembly is not integrated into a padding. For instance and withreference to FIG. 13A, a resuscitation assembly 131 includes a firstelectrode assembly 133 a and a second electrode assembly 133 b eachhaving an electrode pad 135 a, 135 b and motion sensor 137 a, 137 b thatare separate from one another, yet may each be connected to the overallsystem (e.g., via a cable 139 or wireless connection). In someembodiments, a sensor casing containing the motion sensor, where thesensor casing is provided as a small protective covering (e.g., withoutfoam padded material), may be coupled to a patient, separate orseparable from the remainder of the electrode assembly. As an example,the sensor casing and/or motion sensor may include an adhesive or othermaterial that allows the sensor to be attached to and detached from thebody, apart from the electrode pad.

Such a configuration, as shown in FIG. 13A, where motion sensors 137 a,137 b can be freely attached to and detached from the body separate fromthe electrode pad 135 a, 135 b may be relevant if it is preferable forthe location of compressions to vary, or if it is otherwise desirablefor the motion sensor to be positioned at a location away from theelectrode pad. For example, if a patient has had chest surgery, withwounds that do not allow for standard pad placement, it may beadvantageous to have one or more separately attachable motion sensors137 a, 137 b independent of the electrode pad(s) 135 a, 135 b to beattached at any suitable location. Or, in some cases, adjusting thelocation at which chest compressions is applied may give rise toincreased levels of blood circulation. Alternatively, as shown in FIG.13B, the motion sensors 137 a, 137 b may be completely separate from theelectrode pads 135 a, 135 b. For example, as shown, the electrode pads135 a, 135 b may be connected to a system for providing electrotherapythrough the electrode pads, and the motion sensors 137 a, 137 b may beseparately connected to a system for obtaining signals from the motionsensors, for determining one or more parameters related to chestcompressions, such as chest compression depth, rate and/or velocity.

The processor(s) circuitry for processing of signals arising from themotion sensor(s) may be disposed at any suitable location. Suchprocessing may include, for example, integrating acceleration signals toresult in displacement information, or subtracting posterioracceleration or displacement information from anterior acceleration ordisplacement information. Other types of processing and analysis may bepossible. In an example, the processor(s) may be disposed indefibrillator, monitor, computing device, or other medical treatmentapparatus. Accordingly, signals from the motion sensor(s) may betransmitted (e.g., wirelessly or through a cable) to the processor(s) onthe medical treatment apparatus for analysis and, e.g., feedback.Alternatively, for signals transmitted via a wired cable system, theprocessor(s) may be disposed within a reusable portion of the cablesystem. For instance, as discussed herein, the sensor casing, motionsensor and associated cable may form a disposable assembly. Thisdisposable assembly may be plugged into a reusable cable which is, inturn, in electrical communication with a corresponding medical treatmentapparatus (e.g., defibrillator, monitor, etc.). By incorporating theprocessor(s) for processing the signals arising from the motionsensor(s) within the reusable cable, processing of such signals mayoccur quickly and efficiently without unnecessary bandwidth usage fromthe more complex medical treatment apparatus. As a result, theprocessor(s) within the reusable cable may send one or more processedsignals to the medical treatment apparatus (e.g., defibrillator,monitor, CPR system) and/or back to the motion sensor and sensor casing.The medical treatment apparatus may collect the processed signals forfurther data analysis, reporting, or other function(s). In some cases,the sensor casing itself may incorporate circuitry that receives theprocessed compression information and provides an appropriate level offeedback to the user (e.g., LED, display, audio signal for guiding orassisting the user in performing CPR). In other embodiments, theprocessor(s) may be provided with the disposable assembly, for example,located within the sensor casing or associated cable. As an example, themotion sensor and the processor(s) for processing signals from themotion sensor may be provided on the same circuit chip. Communicationbetween the motion sensor(s) and associated processor(s) may be digitaland/or analog in nature.

In another alternative and with reference to FIG. 14, the electrode pads145 a, 145 b of electrode assemblies 143 a, 143 b of a resuscitationassembly 141 may be placed in a certain configuration, such as an A-Aposition where one electrode pad 145 a that includes a motion sensor 147a positioned on an upper surface thereof is placed on the sternum andanother electrode pad 145 b having a separate motion sensor 147 b isplaced on the side of the patient. In such a situation, the separatemotion sensor 147 b can be placed on the back or other suitable locationof the patient, for example, to obtain more accurate or precise chestcompression data even though the electrode pad 145 b is placed on thepatient's side. Cables 149 may be used to connect the electrodeassemblies 143 a, 143 b and motion sensors 147 a, 147 b.

Chest compressions depth, velocity and rate measurements during CPR aretypically made using a single sensor, for example an accelerometercontained in a housing placed on the chest of the patient at an anteriorposition, typically above the sternum. In such methods, the measuredacceleration into the chest is twice integrated to determine chestdisplacement which is used to assess depth and rate of compressions, orintegrated once to determine release velocity. An example of such amethod is described in U.S. Pat. No. 9,125,793, entitled “System fordetermining depth of chest compressions during CPR,” which is herebyincorporated by reference in its entirety. However, such measurementsmay contain error that cannot be accounted for, for example, error dueto movement of a surface under the patient, patient motion and/ormovement during transport, etc. As one example, if the patient is lyingon a soft compressible surface, such as a mattress, the measureddisplacement will include not only the compression into the chest butalso the depth of the deformation of the compressible surface. This canlead to an overestimation of compression depth. As another example, ifthe patient is in a moving ambulance the outside motion may furtheraffect the compression measurements and contribute to error inestimating compression depth.

Resuscitation assemblies of the present disclosure may be utilized toprovide feedback to a user regarding resuscitation activities (e.g.,chest compressions, ventilations) being performed on the patient by therescuer with improved accuracy. More specifically, in operation, arescuer may place the electrode assemblies 1A and 1B of theresuscitation assembly in an A-P orientation, with the electrodeassembly 1A being positioned on the patient's sternum and the electrodeassembly 1B being positioned on the patient's back. Alternatively, asshown in FIG. 12, the electrode assemblies 1A′ and 1B′ of theresuscitation assembly are positioned on the patient in an A-Aorientation. Specifically, in such a configuration, the electrodeassembly 1A′ is positioned on a right side of a chest of the patient 3between the armpit and the sternum, with the portion of the electrodeassembly comprising the motion sensor place substantially above thesternum. The resuscitation assembly 1B′ is an apex electrode assemblyand is positioned on a left side of the chest of the patient 3 overlower ribs of the patient 3. In either configuration, the motion sensors19 of the electrode assemblies 1A, 1B, 1A′, and 1B′ may be provided asthree-axis accelerometers as described hereinabove such thatacceleration in the x, y, and z directions is measured simultaneouslywith each of two sensors incorporated within respective electrodeassemblies.

As noted herein, it can be appreciated that other configurations ofresuscitation assemblies may be employed. In some embodiments, anelectrode assembly including an electrode pad and a motion sensor mightnot require the motion sensor to be directly attached to the electrodepad, or integrated within a padding material (part of a larger sensorhousing) that is directly attached to the electrode pad. For example,the motion sensor may be coupled to the electrode pad via a cable orsome other extension that allows for an electrical connection to theoverall system as shown in FIGS. 13A, 13B, and 14. Or, the motion sensormay be completely free of mechanical attachment to the electrode pad.For instance, the motion sensor may be in wireless communication withthe resuscitation system and be configured to be coupled to the body inany suitable manner (e.g., adhesively attached). In addition, the motionsensor(s) described herein may be provided with a memory that is able tostore data from the time at which use of the motion sensor(s) commences.For example, the motion sensor(s) may be provided with a removable tabthat, upon removal, activates the sensor to begin storing data in thememory. In addition, the motion sensor(s) may be provided with anaudible/visual output system to provide a light or other visual displaymechanism, or speaker or other audible output mechanism, to indicatethat the system is active. The motion sensor(s) and/or associated casingmay also include a chest compression metronome, audible speaker (e.g.,for providing verbal coaching prompts), light (e.g., LED with colorsred/green to indicate whether or not compressions are within acceptableranges), or other component to guide the rescuer in providing chestcompressions. Once the motion sensor is paired to a device (for examplea defibrillator, a desktop top computer, a table computer, a mobilephone, a patient monitor, etc.), the data stored in the memory of themotion sensor is transmitted to the device and integrated in a caserecord for post-case review. In certain examples, the motion sensors maybe wireless with an option for wired communication with a device forreal-time feedback. Alternatively, communication between the motionsensors and the device may be exclusively wireless.

Accordingly, if the motion sensor is able to be moved from one locationto another, the resuscitation system to which the motion sensor iscommunicatively coupled may provide instructions to a user as to whetherthe position of the motion sensor should be adjusted. For example, themotion sensor may be placed at a location unsuitable for gathering chestcompression data. Hence, the system may provide instructions to a userto move the motion sensor to another location on the patient's anatomy.Or, when it is preferred for the location of compressions toperiodically vary from position to position, for purposes of increasingoverall blood circulation, the user may be prompted to detach the motionsensor from the patient's body and attach the motion sensor at adifferent location.

Once the electrode assemblies included with the resuscitation assembliesof the present disclosure are properly placed, they are operativelyconnected to a defibrillator 5 having control circuitry (not shown) andan output device, such as display 6 and/or a speaker (not shown), toprovide output to a user. Such assemblies may be connected via cables 7,or alternatively one or more of the motion sensors may be operativelycoupled to the defibrillator and/or other devices using wirelesstechnology (e.g. Bluetooth, WiFi, radio frequency, near fieldcommunication, etc.). The control circuitry used in the defibrillator 5may be any suitable computer control system, and may be disposed withinthe housing of the defibrillator. Alternatively, the control circuitrymay be disposed within an associated defibrillator, within an associatedmechanical chest compression device, or it may be a general purposecomputer or a dedicated single purpose computer. The control circuitrymay comprise at least one processor and at least one memory includingprogram code stored on the memory, where the computer program code isconfigured such that, with the at least one processor, when run on theprocessor, it causes the processor to perform the functions assigned tothe control circuitry throughout this disclosure. These functionsinclude interpreting the signals from the motion sensors 19, and/orsignals produced by other sensors, to determine compression depth, andproduce signals indicative of the calculated compression depth, andoperate outputs such as speakers or displays to provide feedback to arescuer.

In one example, the output device of the defibrillator 5 providesinformation about patient status and CPR administration quality duringthe use of the defibrillator 5. The data is collected and displayed inan efficient and effective manner to a rescuer. For example, during theadministration of chest compressions, the output device may display ondisplay 6 information about the chest compressions.

The information about the chest compressions is automatically displayedin display 6 when compressions are detected. The information about thechest compressions displayed may include rate (e.g., number ofcompressions per minute) and depth (e.g., depth of compressions ininches or millimeters). The rate and depth of compressions, and/orrelease velocity, can be determined by analyzing readings from themotion sensors 19. Displaying the actual rate and depth data (inaddition to or instead of an indication of whether the values are withinor outside of an acceptable range) is believed to provide usefulfeedback to the rescuer. For example, if an acceptable range for chestcompression depth is between 1.5-2 inches, providing the rescuer with anindication that his/her compressions are only 0.5 inches, can allow therescuer to determine how to correctly modify his/her administration ofthe chest compressions.

More specifically, the control circuitry of the defibrillator 5 isoperatively connected to and programmed to receive and process signalsfrom the motion sensors 19 of the electrode assemblies 1A and 1B todetermine whether at least one of a chest compression depth and rateand/or release velocity during administration of CPR falls within adesired range. The output device of the defibrillator 5 then providesfeedback instructions to the user to maintain the chest compressiondepth and rate during CPR within the desired range.

With the electrode assemblies 1A and 1B positioned in ananterior-posterior position as shown in FIGS. 1A and 1B, in one example,the chest compression depth is calculated by subtracting a distancetraveled by the motion sensor 19 of the electrode assembly 1B from adistance traveled by the motion sensor 19 of the electrode assembly 1A.More specifically, acceleration in the x, y, and z directions ismeasured simultaneously with the two motion sensors 19. The motionsensor 19 of the electrode assembly 1A (i.e., the primary sensor) isplaced anteriorly on the chest while the motion sensor 19 of theelectrode assembly 1B (i.e., the reference sensor) is placed as areference posteriorly on the back as described hereinabove. The primarysensor is to be located in the center of the chest with compressionsoccurring in a substantially perpendicular direction relative to thesensor. The reference sensor may be positioned in alignment with theprimary sensor and the net acceleration along the vertical y-axis (orother axis, such as z-axis, depending on how the patient is orientedwith respect to the accelerometer and the direction of gravity) of thesensors may be used to determine overall compression depth.

In another example, the motion sensor 19 of the electrode assembly 1Bpositioned on the back of the patient provides a signal indicativeacceleration caused by external accelerations, such as the patient beingtransported, and the motion sensor 19 of the electrode assembly 1Aprovides a signal indicative of acceleration caused by a rescuer ormechanical device performing chest compressions on a patient. A signalrepresenting acceleration sensed by the motion sensor 19 of theelectrode assembly 1A (i.e., the device acceleration) is provided to thecontrol circuitry of the defibrillator 5. The device acceleration signalof the electrode assembly 1A records an overall acceleration indicativeof the acceleration caused by compressions (the compressionacceleration) and the acceleration caused by the external accelerations(the external acceleration). The motion sensor 19 of the electrodeassembly 1B further provides a reference acceleration signal for thecontrol circuitry of the defibrillator. The reference accelerationsignal of the electrode assembly 1B records only the externalaccelerations of the patient caused from transporting or otherwisemoving the patient.

Accordingly, the reference acceleration signal may be processed with thedevice acceleration signal to produce an estimated actual acceleration.Once obtained, the estimated actual acceleration may be doubleintegrated to produce an estimated actual chest compression depth asdiscussed, for example, in U.S. Pat. No. 9,125,793. In addition, furtherdetails of the manner in which vehicle motion artifacts can be removedfrom ECG signals based on information provided by secondary motionsensors can be found in U.S. patent application Ser. No. 14/216,225,entitled “ECG Noise Reduction System for Removal of Vehicle MotionArtifact,” which is hereby incorporated by reference in its entirety.For instance, the motion sensor incorporated within the resuscitationassembly 1B, 1B′ placed on the back or side of the patient may recordmovement (e.g., based on detected accelerations) associated withtransport, such as artifacts due to surface features on the roadencountered by the ambulance and/or gurney carrying the patient, and/orvehicle acceleration and deceleration. Accordingly, artifacts resultingfrom patient transport, which may otherwise introduce errors into theoverall estimation for chest compressions (or other CPR parameters) maybe estimated and/or mitigated.

Based on the motion signals recorded from the motion sensors of theelectrode assemblies of the resuscitation assembly of the presentdisclosure, processing circuitry in a system for providing resuscitationassistance may receive and process the recorded data to determinewhether a patient is being transported or not. For instance, if theacceleration signals are associated with patient transport, the systemmay instruct a rescuer to take steps to ensure that the patient isproperly secured. Once the patient is suitably secured, the system mayinstruct the user to administer chest compressions, or anotherresuscitation activity. Or, when rescuers are subject to a scoringsystem that evaluates their performance (e.g., report card) in carryingout resuscitation activities, if it is determined that the patient isbeing transported, the metrics for evaluating the rescuer may beadjusted. For instance, performing manual chest compressions whiletraveling in an ambulance may be more difficult than when not located ina traveling vehicle, and so the rescuer may be given a score whichreflects such conditions. That is, to account for the rescuer beingsubject to conditions where it is more challenging to administer CPR orwhen CPR quality is likely to be compromised, such as during vehicularmotion or transport, the manner in which a rescuer is evaluated may berelaxed and the overall performance evaluation may be higher. Or, forpurposes of evaluating rescuer performance, CPR measurements duringtransport may be discounted from the overall score. Thus, the scoringrubric for assessing the rescuer may account for whether chestcompressions are being administered during transport.

In addition, the system may further be configured to alert a user whenthere is concern for rescuer safety. For example, when a substantialamount of vehicle/transport motion is detected, to ensure that therescuer does not become injured or become a potential liability (being alarge object that can move suddenly within and throughout the vehiclecabin) for other passengers, it may be preferable for the rescuer todiscontinue CPR and rather be placed under a safety restraint (e.g.,seat-belt).

As noted previously, when electrode assemblies comprising one or moremotion sensors in each are placed in the A-P position (front and back),oriented substantially parallel to one another (and the x-y planes ofthe 3-axis accelerometers being substantially parallel to the directionof gravity), and the patient is lying on a compressible surface such asa mattress or thick padding, the system to which the electrodeassemblies are connected may accurately estimate the depth of chestcompressions during CPR by subtracting out the distance traveled by theposterior placed assembly. When such electrode assemblies are placed inan A-A position (front and side), oriented substantially perpendicularto one another, rather than the subtraction technique described herein,the system to which the assemblies are connected may employ a differentalgorithm for estimating the depth of chest compressions. Similarly, thesystem may recognize the electrode assemblies to be placed in alateral-lateral position (side and side), with 3-axis accelerometersoriented substantially parallel to one another and the x-y planes of theaccelerometers being substantially perpendicular to the direction ofgravity. For instance, when recognizing pads placed in an A-A positionor a lateral-lateral, for purposes of estimating the depth of chestcompressions, the system may elect to process data received from onlythe motion sensor positioned on the front of the patient without datafrom the motion sensor positioned on the side of the patient. Otherwise,inaccuracies may arise when the wrong correction algorithm is used, forexample, using an algorithm corresponding to A-P pad placement when infact the pads are placed in an A-A position. Alternatively, if thesystem, by obtaining and processing signals from the sensors indicatingthe orientation of the pads, determines that pads are placed in an A-Aposition, the rescuer may be alerted by an output mechanism of thedefibrillator or other resuscitation apparatus (e.g., monitor, CPRfeedback system) that the pads are in the A-A position, and hence, onlyone of the motion sensors (e.g., anterior placed motion sensor) will beutilized to determine the depth of the chest compressions. The outputmechanism of the defibrillator or other resuscitation apparatus (e.g.,monitor, CPR feedback system) may also provide a recommendation to theuser to use an A-P pad placement if the increased accuracy achieved bythe use of two motion sensors is desired.

Though, in some embodiments, even when the system recognizes that theelectrode pads are placed in the A-A position, the system may stillelect to process data received from both motion sensors. That is,signals from the motion sensor placed closest to the sternum and themotion sensor held by the other pad would both be processed for chestcompression depth. As an example, for A-A placed pads, the electrode padplaced on the side of the patient may be constructed such that themotion sensor extends far enough toward the back of the patient that thesignals therefrom may be useable as a reference for making correctionsin chest compression depth.

The system may recognize electrode assemblies to be placed in an A-Aposition when the separate motion sensors are oriented relative to oneanother at an angle greater than a threshold angle. For example,electrode assemblies oriented substantially perpendicular to one anothermay be considered to be in an A-A position. Conversely, it may berecognized that electrode assemblies are placed in an A-P position whenthe separate motion sensors are oriented relative to one another at anangle greater less than the threshold angle. Hence, electrode assembliesoriented substantially parallel to one another may be considered to bein an A-P position. In various embodiments, the threshold angle is about30 degrees, about 40 degrees, about 50 degrees, or about 60 degrees.

The overall orientation of the patient may also be determined no matterwhat the orientation is of the sensor(s). For instance, even if one ofthe sensors is misplaced or tilted in an otherwise undesirable manner,the vertical axis of the patient (direction perpendicular to the surfaceof the chest) may be determined by comparing the movement and/orposition of the two sensors relative to one another.

With reference to FIG. 15, an example of a process for determining chestcompression depth using the resuscitation assembly of the presentdisclosure is discussed below. First, the rescuer positions theelectrode assemblies 1A and 1B (placed in A-P position) or electrodeassemblies 1A′ and 1B′ (placed in A-A position) on the patient (seeblock 200). Once the electrode assemblies are placed on the patient, asignal is obtained from each motion sensor 19 to provide a baselineacceleration of gravity (see block 202). By measuring the baselineacceleration of gravity, the system determines the initial orientationof each motion sensor of the electrode assemblies and rotates thereference sensor (i.e., motion sensor 19 of the electrode assemblypositioned anteriorly or posteriorly) to the same plane as the primarysensor (i.e., motion sensor 19 positioned anteriorly on the patient'ssternum). This process reduces errors caused by a non-parallel alignmentof the primary and reference sensors. In addition, the baselineaccelerations measured by the reference sensor can be used to determinewhether the reference sensor was placed posteriorly or anteriorly (seeblock 204). If an anterior placement is used for the reference sensor(see the configuration of FIG. 12), the accelerations detected by themotion sensor 19 of resuscitation assembly 1B′ (i.e., the referencesensor) are disregarded and compression depth is determined solely basedon a signal from motion sensor 19 of electrode assembly 1A′ (i.e., theprimary sensor as discussed hereinabove (see block 206)). If a posteriorplacement is used for the reference sensor (see the configuration ofFIGS. 1A and 1B), the chest compression depth is calculated bysubtracting a distance traveled by the motion sensor 19 of the electrodeassembly 1B (i.e., the secondary sensor) from a distance traveled by themotion sensor 19 of the electrode assembly 1A (i.e., the primary sensor)along the direction in which chest compressions are administered, asdescribed hereinabove (see block 208).

Another use for resuscitation assemblies of the present disclosure inconjunction with defibrillator 5 is to accurately detect compressiondepth when performing CPR on smaller patients such as infants. Foradults, CPR chest compressions are delivered while the patient issupine, typically supported by a sufficiently rigid surface (a floor,gurney, or hospital bed). For infants, on the other hand, CPR chestcompressions may be provided with one of two methods, discussed below.

The first method for administering CPR chest compressions to an infant,which may be preferable in some instances, is the two-thumb method asshown in FIG. 16. This method entails grasping the infant's thorax withboth hands, placing both thumbs over the sternum (with the fingerssupporting the back of the infant) and using the thumbs to providecompressive force to the sternum. More specifically, the infant issupported on a surface in the supine position. A CPR provider placeshis/her hands around the infant's thorax, thereby placing his/her thumbsover the infant's sternum with his/her fingers wrapping over theaxillary area under the infant's arms and around the infant's back. Inthis method, the CPR provider squeezes the infant's thorax, with thethumbs pressing on the sternum, to push the sternum toward the spine.These compressions should be accomplished at a rate of 100 compressionsper minute and a depth of about one-third of the total thickness of thethorax (e.g., 1.5 inches (3.8 cm) for a thorax thickness of about 4.5inches).

The second method for administering CPR chest compressions to an infant,which may be preferable for lone rescuers, is often referred to as thetwo finger method. This method entails compression of the infant's chestwith two fingers placed over the inter-mammary line (superior to thexiphoid process). Compressions are generally recommended to be about onethird of the thickness of the thorax (e.g., 1.5 inches (3.8 cm) for athorax thickness of 4.5 inches (11.4 cm)), which is a rough estimate ofinfant chest thickness which is, of course, variable depending on theage/size of the infant patient). The chest should be released completelyafter each compression.

According to the American Heart Association, the two-thumb-encirclinghands technique is preferred over the two-finger technique because thetwo-thumb technique has been suggested to give rise to higher coronaryartery perfusion pressure, resulting more consistently in appropriatedepth or force of compressions, and may generate higher systolic anddiastolic pressures in the patient.

By positioning a motion sensor 19 on both the back and the chest of theinfant through the use of electrode assemblies 1A and 1B, thecompression depth of compressions performed on an infant using one ofseveral techniques, such as the two-thumb, two finger and/or single palm(where a palm is placed underneath the patient as a backboard) techniquecan be accurately determined by placing the thumbs or fingers over therespective motion sensors and subtracting a distance traveled by themotion sensor 19 of the electrode assembly 1B from a distance traveledby the motion sensor 19 of the resuscitation assembly 1A. In some cases,the use of the two sensor configuration in the A-P position to estimatechest compression depth may be even more effective when using thetwo-thumb method because this method often involves squeezing of thepatient between the thumbs and the fingers, resulting in movement bothon the front and back. Though, it can be appreciated that the two sensorconfiguration may also be effective when using the two finger and/orsingle palm technique, particularly when the patient is lying on acompressible surface. In fact, the two sensor configuration may beeffective as rescuers may switch between techniques (e.g., two-thumb,two finger, single palm, etc.).

By implementing a dual sensor approach in accordance with the presentdisclosure, the estimated chest compression depth may be compared withdesired chest compression ranges (e.g., based on AHA/physicianrecommendations), and appropriate feedback and/or instructions can beprovided to a rescuer as to the quality of chest compressionsadministered based on the comparison of estimated compression depth anddesired compression ranges. Such feedback may include, for example,prompts that provide instruction(s) to the rescuer of whether to providedeeper or shallower compressions, or to maintain the current depth. Anyappropriate prompts may be employed, such as audio prompts (e.g.,voice/spoken cues, beeps of varying tone/pattern, etc.), visual (e.g.,display screen with text, colors and/or graphics), tactile (e.g.,vibrations), or prompts according to another suitable method. It shouldalso be appreciated that while several of the embodiments describedherein may apply to pediatric or small patients, such configurations mayalso apply, or may be more preferable, for adult or larger patients.

It can be appreciated that chest compression depth can be determined ina number of different ways utilizing the pair of motion sensors providedin the electrode assemblies of the resuscitation assembly describedherein. For instance, raw acceleration signals may be subtracted andthen processed (e.g., double integrated) to calculate net distance. Or,before subtraction, raw acceleration signals may be processed (e.g.,double integrated) to yield distance values and then the respectivedistance values may be subtracted accordingly. In other examples, one orboth of the motion sensors may be velocity or displacement sensors, andthe signals obtained therefrom can be processed to determine chestcompression depth or other chest compression parameters such as rate,release velocity, etc.

To further illustrate one of the above examples, one motion sensor,positioned on the back of the patient for example, provides a signalindicative of acceleration caused by external accelerations, such as thepatient being transported, the patient being placed on a compressiblesurface, etc., and another motion sensor, positioned on the chest of thepatient for example, provides a signal indicative of acceleration causedby a rescuer performing chest compressions on a patient. The signalindicative of the acceleration caused by compressions (the compressionacceleration) is subtracted from the signal indicative of accelerationcaused by the external accelerations (the external acceleration) toproduce a corrected acceleration value (e.g., estimated actualacceleration). Once obtained, the corrected acceleration value may bedouble integrated to produce a corrected chest compression depth (e.g.,estimated actual chest compression depth). Using such a method may beuseful to save computational resources in that only one processing stepis performed, i.e., the signal representing corrected acceleration isthe only signal that is integrated, which may save processing steps.Further, the software and/or hardware component that performs theprocessing (e.g., integration) may only need to input a singleacceleration value regardless of whether the acceleration signal(s) hadpreviously been subtracted or processed in another manner.

Illustrating another example, the chest compression depth may becalculated by subtracting a distance traveled by the second motionsensor from a distance traveled by the first motion sensor. In such aninstance, the signal indicative of acceleration caused by externalaccelerations is double integrated to determine the distance traveled bythe second motion sensor and the signal indicative of accelerationcaused by a rescuer performing chest compressions on a patient is doubleintegrated to determine the distance traveled by the first motionsensor. The distance traveled by the second motion sensor is thensubtracted from the distance traveled by the first motion sensor toprovide the compression depth.

The resuscitation assemblies discussed herein may also be utilized toprovide feedback to a user regarding the surface upon which a patient isplaced. More specifically, the output device may provide instructions toa user for a surface upon which the patient is positioned to be changedbased on information sensed from the motion sensor 19 of the electrodeassembly 1A and the motion sensor 19 of the electrode assembly 1B. Forexample, and with reference to FIGS. 17 and 18, in operation, a user mayplace the electrode assemblies 1A and 1B in an A-P orientation with theelectrode assembly 1A being positioned on the patient's sternum and theelectrode assembly 1B being positioned on the patient's back as shown inFIGS. 1A and 1B (see block 400 of FIG. 18).

Once the electrode assemblies 1A, 1B of the resuscitation assembly areproperly placed, they are operatively connected via cables 7 to adefibrillator 5 having control circuitry (not shown) and the outputdevice, such as display 6 and/or a speaker (not shown), to provideoutput to a user. By way of example, and as discussed above, the outputdevice provides information about patient status and CPR administrationquality during the use of the defibrillator 5. The information about thechest compressions is automatically displayed in display 6 whencompressions are detected. The information about the chest compressionsdisplayed may include rate (e.g., number of compressions per minute) anddepth (e.g., depth of compressions in inches or millimeters). The rateand depth of compressions can be determined by analyzing readings fromthe motion sensors 19.

It is common practice to place a patient on a sufficiently rigid surface(e.g., a floor, gurney, backboard, or hospital bed) prior to initiatingchest compressions. However, if the patient is not provided on such asurface and is instead placed on a compressible surface (e.g., adults inhospitals are commonly treated on compressible surfaces, and mattressesfor pediatric patients mattress can be especially compressible, evenmore so than adult mattresses), such as a soft mattress, the rescuer mayneed to perform more intense work to achieve the required compressiondepth. As a result, the rescuer may either have difficulty achievingsufficient compression depth and/or fatigue quickly. Or, without thefeedback mechanism, the rescuer may have the impression of reaching asufficient depth without actually achieving it.

With reference to FIG. 17, a patient 3 is illustrated as beingpositioned on a compressible surface 71, such as a mattress, where anelectrode assembly 1A having a motion sensor 19 is positioned anteriorlyand an electrode assembly 1B having a motion sensor 19 is positionedposteriorly. In operation, chest compressions are performed on thepatient 3 by a rescuer as denoted by arrow F. The measured displacement(d_(A)) obtained by motion sensor 19 of electrode assembly 1A includesnot only the displacement of the compression into the chest (d₁) butalso the displacement caused by deformation of the compressible surface(d_(P)). As discussed hereinabove, this can lead to an overestimation ofcompression depth. By providing a motion sensor in both the anteriorlypositioned electrode assembly 1A and the posteriorly positionedelectrode assembly 1B, this overestimation of the compression depth maybe corrected to provide a more accurate determination of chestcompression depth. The actual compression depth can be calculated bysubtracting the displacement of the motion sensor 19 of the electrodeassembly 1B (i.e., the secondary sensor) from the displacement of themotion sensor 19 of the electrode assembly 1A (i.e., the primarysensor). More specifically, the displacement of the motion sensor 19 ofthe electrode assembly 1A corresponds to displacement d_(A) in FIG. 17and includes both the displacement of the compression into the chest(d₁) and the displacement caused by deformation of the compressiblesurface (d_(P)). The displacement of the motion sensor 19 of theelectrode assembly 1B only measures the displacement caused bydeformation of the compressible surface (d_(P)). Accordingly, bysubtracting the displacement caused by deformation of the compressiblesurface (d_(P)) from the displacement of the motion sensor 19 of theelectrode assembly 1A (d_(A)=d₁+d_(P)), the actual compression depth,corresponding to displacement of the compression into the chest (d₁) canbe obtained.

In addition, with reference to FIG. 18, by incorporating a motion sensor19 in both the anteriorly positioned electrode assembly 1A and theposteriorly positioned electrode assembly 1B, a motion sensor 19 isprovided on both the chest and back of the patient 3. The controlcircuitry of the defibrillator 5 is operatively connected to andprogrammed to receive and process signals from the motion sensors 19 ofthe electrode assemblies 1A and 1B and may determine whether the patient3 is positioned on a compressible surface. More specifically, the motionsensor 19 of the electrode assembly 1A may produce a first signalrepresentative of acceleration caused by compressions and the motionsensor 19 of the electrode assembly 1A may produce a second signalrepresentative of other types of accelerations, such as acceleration dueto movement on a compressible surface (see block 402). These signals arethen processed (see block 404) to determine whether the amount ofdisplacement arising from the compressible surface meets a thresholdgreat enough to recommend that the surface underneath the patient bechanged (see block 406). Such a threshold may be correlated to theamount of work that a rescuer would have to exert to achieve chestcompressions that fall within a desired range. For example, to alleviatethe rescuer of excess effort, a threshold may be set such that if thedisplacement arising from the compressible surface is greater than 10%(e.g., between 10-100%), greater than 25% (e.g., between 25-100%),greater than 50% (e.g., between 50-100%), greater than 75%, or greaterthan 100% of the recommended compression depth or another metric (e.g.,comparison to the total displacement of the anterior sensor), then theuser may be provided with a suggestion or instruction that theunderlying surface on which the patient resides be changed. Such aninstruction may be for a backboard to be placed underneath the patient,or for the patient to be moved from the existing relatively soft surfaceto a harder surface. The output device of the defibrillator 5 mayprovide feedback instructions to a user for a surface upon which thepatient 3 is positioned to be changed if it is determined that thepatient 3 is provided on a compressible surface that meets the setthreshold (see block 408 of FIG. 18). This feedback can be real-timefeedback in the form of an audible, visual or tactile indicationrequesting that the rescuer position a backboard beneath the patient 3or move the patient 3 to a more rigid surface. Alternatively, thefeedback may be issued at the end of the rescue sequence advising therescuer to use a backboard in future CPR situations. In situations wheredisplacement arising from a surface upon which the patient 3 is placedis less than the predetermined threshold, the system assumes the patient3 is positioned on a rigid surface and the defibrillator 5 providesfeedback to the rescuer regarding the quality of compressions asdiscussed hereinabove.

One challenge in using two motion sensors such as motion sensors 19 ofelectrode assemblies 1A and 1B or 1A′ and 1B′, for example, is that thetwo sensors may not be in the same orientation. By measuringacceleration in three dimensions, when the motion sensors 19 areconfigured as three-axis accelerometers, it is possible to determine abaseline orientation of each motion sensor 19 and then rotate thereference sensor (i.e., the motion sensor 19 of the resuscitationassembly 1B) to be in the same plane as the primary sensor (i.e., themotion sensor 19 of the resuscitation assembly 1A). It can beappreciated that this reference rotation may be applied to signalsderived from both motion sensors using techniques known to those ofordinary skill in the art.

For certain cases, the rotation of a baseline vector of each motionsensor 19 may be determined by averaging a quiet period with nomovement. From these vectors the angles (α, β, γ) between the primaryand reference sensors are calculated. A rotation matrix is thencalculated to first rotate the reference vector around the Z-axis by anangle γ (see Equation 1 below) and then rotate the vector again aroundthe X-axis by an angle α (see Equation 2 below). Each measurement on thereference sensor is multiplied by the rotation matrix R_(x)R_(z).

$\begin{matrix}{R_{z} = \begin{bmatrix}{\cos(\gamma)} & {- {\sin(\gamma)}} & 0 \\{\sin(\gamma)} & {\cos(\gamma)} & 0 \\0 & 0 & 1\end{bmatrix}} & {{Equation}\mspace{14mu} 1} \\{R_{x} = \begin{bmatrix}1 & 0 & 0 \\0 & {\cos(\alpha)} & {- {\sin(\alpha)}} \\0 & {\sin(\alpha)} & {\cos(\alpha)}\end{bmatrix}} & {{Equation}\mspace{14mu} 2}\end{matrix}$

After the rotation is performed, the compression depth is calculatedusing the acceleration component as measured in the directionperpendicular to the chest surface (e.g., y-axis acceleration) from theprimary and reference sensor. The depth is calculated by subtracting theacceleration in the direction perpendicular to the chest surface asdetected by the motion sensor 19 of the resuscitation assembly 1B placedposteriorly on the patient 3 from the acceleration in the directionperpendicular to the chest surface as detected by the motion sensor 19of the electrode assembly 1A placed anteriorly on the patient 3.

Alternatively, a rotation calibration may be performed via a normalizedcross product calculation, such as that described in the journal articleby Emod Kovacs, entitled “Rotation about an arbitrary axis andreflection through an arbitrary plane,” published in AnnalesMathematicae et Informaticae (40), 2012, pp. 175-186. In this method, toperform the rotation calibration, the baseline vector of each sensor isdetermined by averaging a quiet period with no movement. To rotate onevector to another, the vectors are first transformed so the axis ofrotation is coordinate with the Z-axis. A rotation around the Z-axis ofthe angle between the two vectors is then performed and the inverse ofthe transformation is applied to the vectors. The axis of rotation isthe normalized cross product of the reference sensor vector and theprimary sensor vector.

Upon suitable calibration, the two motion sensors 19 may also be used todetect the direction in which chest compressions are administered suchthat a determination of whether a rescuer is performing compressions atan angle relative to the motion sensor 19 of a resuscitation assemblyplaced on the thorax can be made by the control circuitry. It may bepreferable for chest compressions to be administered in a verticaldirection relative to the patient (when lying down), i.e., substantiallyperpendicular to the surface of the chest. However, rescuersadministering chest compressions may have a tendency to push at an anglerelative to the vertical direction, for example, due to poor CPRhabits/education, fatigue, etc.

Accordingly, whether placed in an A-P configuration or an A-Aconfiguration, a resuscitation system incorporating motion sensors inmultiple electrode assemblies may be configured to sense the angle atwhich the rescuer is pushing relative to the patient, and advise as towhether the rescuer should alter the direction in which chestcompressions are being administered. For example, if the rescuer isadministering chest compressions at a 45 degree angle relative to thevertical direction (perpendicular to the chest), then a first motionsensor (placed on the patient's chest) may be expected to move along adirection angled at approximately 45 degrees with respect to thevertical, as referenced by the second motion sensor (placed on thepatient's back or side). Or, the manner in which the rescuer administerschest compressions, if delivered at a non-vertical angle relative to thepatient, may cause the first motion sensor to tilt or roll. For caseswhere the angle at which chest compressions is determined based on thetilt or roll of a motion sensor, gyroscopes may be appropriatelyincorporated and the correction algorithm may account for the detectedtilt or roll of the motion sensor. Hence, the resuscitation system maydetect or otherwise estimate the angle at which chest compressions arebeing delivered.

As a result, based on the acceleration information gathered from the twosensor arrangement, the system may provide instructions to the rescuerto alter the manner and/or direction in which chest compressions arebeing delivered so as to minimize or otherwise reduce the angle ofcompression. Such instructions may be provided in the form of audio,visual, tactile feedback, or a combination thereof. As an example, thesystem may present a display screen or interface to the rescuer of theexisting angle of compressions, as estimated via the dual motion sensorconfiguration. The display screen or interface may then provide anindication to the user that the direction in which chest compressions isdelivered should be changed and how that change in direction may beaccomplished. For example, the system may present a graphical display ofthe angle of chest compressions in real-time so that the rescuer mayknow how the direction of chest compressions should be immediatelyaltered. Or, the system may provide express instructions to the rescuerfor how the angle at which chest compressions are delivered should bealtered. Or, upon sensing the misalignment in the direction of chestcompressions, if the rescuer does not change the direction ofcompression, the system may instruct the rescuer to push harder so thatthe chest compressions will be deep enough. Another type of feedbackmight be providing an alert or other notification informing the rescuerthat more work is being performed than necessary.

In yet another example, the motion sensors 19 of resuscitationassemblies in accordance with the present disclosure may be used tosense a rate of ventilations for a patient. More specifically,ventilations (manual or automated) administered to the patient, inbetween and/or appropriately synchronized between chest compressions,may cause movement of the patient's body. Such movements arising due tothe ventilations may be detectable by the motion sensors of theresuscitation assemblies (e.g., anterior sensor may detectventilation-induced movements), giving rise to a waveform (e.g.,displacement as a function of time) representative of back and forthmovement of the motion sensors. The frequency of peaks and valleys mayprovide an indication of the rate of ventilations delivered to thepatient. Accordingly, the system with which the resuscitation assembliesare in communication may provide suitable indication and/or feedback(e.g., audio, visual, tactile) as to whether the rate of ventilationsshould be faster or slower, or how the ventilations may be bettersynchronized with chest compressions.

In still another example, as discussed hereinabove, the motion sensors19 of resuscitation assemblies in accordance with the present disclosuremay be used to determine whether the electrode assemblies are placed inan A-A, A-P or lateral-lateral position based on the orientation of themotion sensors 19 and/or distance relative to one another. Once theposition of the electrode assemblies is determined, the system mayadjust one or more resuscitation parameters, e.g., feedback and/orinformation provided to the rescuer.

With reference to FIG. 19, a resuscitation assembly 500 comprises afirst electrode assembly 502, a second electrode assembly 504, and a CPRpad 506 associated with the first electrode assembly 502. In variousembodiments, each of the electrode assemblies 502, 504 may have a motionsensor 19 incorporated therewith (e.g., motion sensor may be embeddedwithin a portion of the electrode assembly). Electrode assemblies 502,504 may be placed in an A-A position with electrode assembly 502positioned on an upper right side of a chest of the patient 3 betweenthe shoulder and the sternum and the electrode assembly 504 positionedon a lower left side of the chest of the patient 3 over lower ribs ofthe patient 3.

In certain forms of treatment, rather than placement in the A-A positionshown in FIG. 19, a rescuer may place the first electrode assembly 502and the second electrode assembly 504 in an A-P position. In some cases,placement of electrode assembly 502 on the patient's sternum area (asmay happen during a rescue) and electrode assembly 504 on the patient'sback may lead to an ECG signal that appears inverted and/or the pacingvector associated with the electrode placement may be oriented in anundesirable direction through the heart. In such instances, whenelectrode assemblies are placed in an A-P position as shown in FIGS. 20Aand 20B, or other configuration that may lead to an inverted ECG signaland/or pacing vector oriented in an undesirable direction, the systemmay be configured to provide desirable corrections to the ECG signaland/or pacing vector to orient it in the preferred direction. Or, thesystem may prompt the rescuer to place the pads in an orientation thatgives rise to a more intuitive ECG signal and/or pacing vector withpreferred directionality.

By providing the electrode assemblies 502, 504 with motion sensors 19,the control circuitry used in the defibrillator 5 can be configured todetermine the location of each of the electrode assemblies 502, 504based on the orientation of the motion sensors 19 and/or distancerelative to one another as described hereinabove. If the controlcircuitry determines that first electrode assembly 502 is positioned onthe patient's sternum and the electrode assembly 504 on the patient'sback as shown in FIGS. 20A and 20B based on the signals from the motionsensors 19, for some embodiments, the control circuit can invert orotherwise adjust the ECG signal such that it is displayed correctly onthe display 6 of the defibrillator 5 and adjust the pacing vector (e.g.,reverse the direction of the pacing vector) such that it is provided inthe correct direction.

While various examples and configurations of the electrode assembliesincorporating motion sensors have been described hereinabove, this isnot to be construed as limiting the present disclosure as various otherexamples and configurations have been envisioned in which each of theelectrode assemblies includes at least one motion sensor. For instance,various other configurations have been envisioned for use with pediatricpatients, infant patients, and adult patients.

With reference to FIGS. 21A and 21B, a resuscitation assembly for usewith a pediatric patient is illustrated. This resuscitation assemblyincludes a pair of electrode assemblies 600, 602. Electrode assembly 600is configured to be attached anteriorly to the pediatric patient's chestand is similar in construction as electrode assembly 1A describedhereinabove. Electrode assembly 602 is configured to be attachedposteriorly to a patient's back (see FIG. 21B). The electrode assembly602 may include a flexible electrode pad 604 having a therapy side (notshown) configured to be coupled to the patient 3 and substantiallyconform to the patient's anatomy. The therapy side includes conductivematerial (not shown), facing toward the body of the patient 3, adaptedto provide therapeutic treatment to the patient.

The electrode assembly 602 may further include a motion sensor 101positioned within a sensor casing 99. The motion sensor 101 and sensorcasing 99 may be similar to the motion sensor 101 and sensor casing 99shown in FIG. 10. The sensor casing 99 may be coupled to the electrodepad 604 by positioning the sensor casing 99 on an upper surface of theelectrode pad 604 at a bottom extension portion 606. The extensionportion 606 may form a pouch or other receptacle within which the sensorcasing 99 may be disposed. In some embodiments, the sensor casing 99 isoptionally removable from the pouch, and may be placed at any suitablelocation on or near the patient. A securing portion 608 may bepositioned over the sensor casing 99 to secure the sensor casing 99 onthe upper surface of the electrode pad 604 at the bottom extensionportion 606. In such a configuration, the sensor casing 99 may beremovably secured between the upper surface of the bottom extensionportion 606 and the bottom surface of the securing portion 608, therebyallowing the sensor to be easily replaced and/or moved to anotherlocation.

It can be appreciated that the sensor casing and the electrode pad maybe removably coupled by any suitable manner. As discussed above, theelectrode pad may have a pouch or receptacle for holding the sensorcasing in place, yet the sensor casing may be easily separated therefromwhen desired. In one example, the backing of the electrode pad may haveperforations, a slightly scored or nicked region, cut marks, etc. thatallow for tearing of a weakened region so that the sensor may beremoved. The electrode pad may further include a suitable adhesive sothat the sensor may be reattached or coupled thereto. In anotherexample, the sensor may be adhered to an upper surface of the electrodepad backing where the backing includes a liner material such that thesensor may be peeled off and adhered elsewhere. Alternatively, thesensor casing and the electrode pad may have complementary couplingcomponents, for example, hook and loop fasteners, mutually attractingmagnets, other fastening elements, etc. Or, the sensor casing may havean adhesive material that allows for repositioning from the electrodepad to a different surface (e.g., patient's skin). In furtherembodiments, the adhesive for attaching the sensor to the electrode padand/or surface of the patient may be effective in moist environments,such as in neonatal situations where birthing fluid is present. Forexample, a moisture activated or water-based adhesive may be employedsuch that when the sensor casing is peeled off the pad and reattached,the adhesive is more effective in adhering to the point of contact.

In addition, by utilizing a motion sensor 101 and sensor casing 99having a low profile such as the one shown in FIG. 10 and positioningthe sensor casing at a bottom extension portion 606 of the electrode pad604, the remaining portions of the flexible electrode pad 104 have moreflexibility in adhering to the patient 3, thereby reducing thelikelihood that the electrode pad 604 lifts off from the patient 3. Withreference to FIG. 22, the flexible electrode pad 104 may also beconfigured to be significantly thinner than the electrode assembly 1Ashown in FIG. 1. For instance, the thickness of the flexible electrodepad may be less than approximately 10 cm, less than approximately 5 cm(e.g., approximately 1 mm-5 cm), less than approximately 1 cm (e.g.,approximately 1-10 mm), less than approximately 5 mm (e.g.,approximately 0.1-5 mm), less than approximately 4 mm (e.g.,approximately 0.1-4 mm), less than 3 mm (e.g., approximately 0.1-3 mm),less than approximately 2 mm (e.g., approximately 0.1-2 mm), less thanapproximately 1 mm (e.g., approximately 0.1-1 mm), or may fall withinanother appropriate range.

With reference to FIGS. 23A and 23B, another example of a resuscitationassembly for use with a pediatric patient is illustrated. In thisexample, the resuscitation assembly includes a pair of electrodeassemblies 700, 702. Electrode assembly 700 is configured to be attachedanteriorly to the pediatric patient's chest and is substantially thesame as electrode assembly 1A described hereinabove except that themotion sensor incorporated therein is a smaller motion sensor such asthe motion sensor 101 incorporated into sensor casing 99 as shown inFIG. 10. The use of such a motion sensor is beneficial for use inpediatric patients in that it is smaller and therefore takes up lessspace on the patient's anatomy. Electrode assembly 702 is configured tobe attached posteriorly to a patient's back (see FIG. 23B). Theelectrode assembly 702 may include a flexible electrode pad 704 having atherapy side (not shown) configured to be coupled to the patient 3 andsubstantially conform to the patient's anatomy. The therapy sideincludes conductive material (not shown), facing toward the body of thepatient 3, adapted to provide therapeutic treatment to the patient.

As shown in this example, the motion sensor 101 associated with theelectrode assembly is not integrated into a padding. Instead, theelectrode assembly 702 and motion sensor 101 are separate from oneanother, yet may each be connected to the overall system (e.g., viacables 706 or wireless connection). In some embodiments, the sensorcasing 99 containing the motion sensor 101, where the sensor casing 99is provided as a small protective covering (e.g., without foam paddedmaterial), may be coupled to a patient, separate from the remainder ofthe electrode assembly 702. As an example, the sensor casing 99 and/ormotion sensor 101 may include an adhesive or other material that allowsthe sensor to be attached to and detached from the electrode pad and/orthe body, apart from the electrode pad. In addition, in such an example,the sensor casing 99 may be attached to various locations on theelectrode pad 704 as shown in FIG. 23B. As an example, the sensor casing99 may be initially adhered to the electrode pad 704, and then may beremovable for subsequent attachment to the body of the patient.

Such a configuration, as shown in FIG. 23B, where motion sensor 101 canbe freely attached to and detached from the body separate from theelectrode pad 604 may be relevant if it is preferable for the locationof compressions to vary, or if it is otherwise desirable for the motionsensor to be positioned at a location away from the electrode pad.

With reference to FIGS. 24A and 24B, another example of a resuscitationassembly for use with a pediatric patient is illustrated. Thisresuscitation assembly includes a pair of electrode assemblies 800, 802.Electrode assembly 800 is configured to be attached anteriorly to thepediatric patient's chest and comprises a flexible electrode pad 804having a therapy side (not shown) configured to be coupled to thepatient 3 and substantially conform to the patient's anatomy. Thetherapy side includes conductive material (not shown), facing toward thebody of the patient 3, adapted to provide therapeutic treatment to thepatient. The electrode assembly 800 may further include a motion sensor806 positioned within a sensor casing 808. The motion sensor 806 andsensor casing 808 may be similar to the motion sensor 101 and sensorcasing 99 shown in FIG. 10. The sensor casing 808 may be coupled to theelectrode pad 804 by positioning the sensor casing 808 on an uppersurface of the electrode pad 804. As discussed herein, the outer surfaceof the sensor casing 808 may include a texture or other material toprevent slippage of the rescuer's hands or otherwise enhance overallcomfort during compressions. In addition, the lead wires 810 a, 810 bextending from the electrode pad 804 and the sensor casing 808,respectively, are configured to extend from the side of these elementsrather than from the bottom as in other examples. Such a configurationmay be desirable if a rescuer wants to direct the wires away from theabdomen of a patient. For example, if a patient has had abdominalsurgery, with wounds in an area where wires, tubes or other instrumentswould be located, in close proximity with conventional electrodes, itmay be advantageous to utilize an electrode assembly, such as electrodeassembly 804, with the wires 810 a, 810 b extending to the side awayfrom the wound location. In addition, the side extending wires may moreeasily lead toward a defibrillator, monitor or other computing systemfor processing signals from the sensor. Otherwise, sensor wiresextending down toward the abdomen, as may typically be the case, may becomparatively more cumbersome to handle. The posterior electrode pad mayalso include side extending wires, which are generally useful to reducethe overall contact area with the patient, and for smaller patientswhere space on the patient's back is limited.

Electrode assembly 802 is configured to be attached posteriorly to apatient's back (see FIG. 24B). The electrode assembly 802 issubstantially similar in construction as electrode assembly 602 shown inFIG. 21B except that the dimensions of the electrode assembly 802 aresmaller and more streamlined. The lead wire 812 is configured to extendfrom the bottom of the electrode assembly 802 as shown in FIG. 24B.Alternatively, as shown in FIG. 24C, the lead wire 812 may extend fromthe side of the electrode assembly 802 for the reasons describedhereinabove with reference to FIG. 24A.

With reference to FIGS. 25A and 25B, a resuscitation assembly for usewith an adult patient is illustrated. This resuscitation assemblyincludes a pair of electrode assemblies 900, 902. Electrode assembly 900is configured to be attached anteriorly to the pediatric patient's chestand is substantially similar in construction as electrode assembly 1Adescribed hereinabove except that the shape of the electrode pad 904 istriangular rather than round. Electrode assembly 902 is configured to beattached posteriorly to a patient's back (see FIG. 25B). The electrodeassembly 902 is substantially similar in construction as electrodeassembly 1B described hereinabove except that the sensor housing 13 ispositioned at an upper corner of the flexible electrode pad 906 ratherthan covering most of the surface of the flexible electrode pad.

With reference to FIGS. 26A and 26B, another example of a resuscitationassembly for use with an adult patient is illustrated. Thisresuscitation assembly includes a pair of electrode assemblies 1000,1002. Electrode assembly 1000 is configured to be attached anteriorly tothe adult patient's chest and is substantially the same as electrodeassembly 700 described hereinabove except that the shape of theelectrode assembly 1000 is triangular rather than round and theelectrode assembly 1000 has larger dimensions. Electrode assembly 902 isconfigured to be attached posteriorly to a patient's back (see FIG.25B). The electrode assembly 902 is substantially similar inconstruction as electrode assembly 600 described hereinabove except thatit has larger dimensions. In some embodiments, such pads may include ECGelectrodes, which allow for monitoring of ECG without requiring separateleads for pacing. In addition, the sensor casings 99 of each of theseelectrode assemblies 1000 and 1002 are removable and adjustable. Forexample, a rescuer may be able to remove the sensor casing 99 of theanterior electrode assembly 1000 from the primary position shown in FIG.26A to some other location. If the patient has a surgical wound, it maybe necessary to leave the sensor casing near the sternum but move theelectrode pad of the electrode assembly 1000 to a different location.

With reference to FIGS. 27A and 27B, an example of a resuscitationassembly for use with neonatal patients is illustrated. Thisresuscitation assembly is designed specifically for use on an infantduring CPR procedures as was described with reference to FIG. 16. Theresuscitation assembly comprises a pair of electrode assemblies 1100,1102. Electrode assembly 1100 is configured to be attached anteriorly tothe pediatric patient's chest. The electrode assembly 100 may include aflexible electrode pad 1104 having a therapy side (not shown) configuredto be coupled to the infant patient 3 and substantially conform to thepatient's anatomy. The therapy side includes conductive material (notshown), facing toward the body of the infant patient 3, adapted toprovide therapeutic treatment to the patient. The electrode assembly1100 may further include a motion sensor 101 positioned within a sensorcasing 99. The motion sensor 101 and sensor casing 99 may be similar tothe motion sensor 101 and sensor casing 99 shown in FIG. 10. The sensorcasing 99 may be coupled to the electrode pad 1104 by positioning thesensor casing 99 on an upper surface of the electrode pad 1104 at abottom portion thereof.

Electrode assembly 1102 is configured to be attached posteriorly to apatient's back (see FIG. 27B). The electrode assembly 1102 may include aflexible electrode pad 1106 having a therapy side (not shown) configuredto be coupled to the infant patient 3 and substantially conform to thepatient's anatomy. The therapy side includes conductive material (notshown), facing toward the body of the infant patient 3, adapted toprovide therapeutic treatment to the patient. The electrode assembly1102 may further include a motion sensor 101 positioned within a sensorcasing 99. The motion sensor 101 and sensor casing 99 may be similar tothe motion sensor 101 and sensor casing 99 shown in FIG. 10. The sensorcasing 99 may be coupled to the electrode pad 1106 by positioning thesensor casing 99 on an upper surface of the electrode pad 1106 at abottom extension thereof.

Although a dual motion sensor resuscitation assembly has been describedin detail for the purpose of illustration based on what is currentlyconsidered to be the most practical examples, it is to be understoodthat such detail is solely for that purpose and that the invention isnot limited to the disclosed examples, but, on the contrary, is intendedto cover modifications and equivalent arrangements. For example, it isto be understood that this disclosure contemplates that, to the extentpossible, one or more features of any example can be combined with oneor more features of any other example.

As used herein, the singular form of “a”, “an”, and “the” include pluralreferents unless the context clearly dictates otherwise.

As used herein, the terms “right”, “left”, “top”, and derivativesthereof shall relate to the invention as it is oriented in the drawingfigures. However, it is to be understood that the invention can assumevarious alternative orientations and, accordingly, such terms are not tobe considered as limiting. Also, it is to be understood that theinvention can assume various alternative variations and stage sequences,except where expressly specified to the contrary. It is also to beunderstood that the specific devices and processes illustrated in theattached drawings, and described in the following specification, areexamples. Hence, specific dimensions and other physical characteristicsrelated to the embodiments disclosed herein are not to be considered aslimiting.

Unless otherwise indicated, all numbers expressing dimensions, materialparameters, or other values used in the specification and claimsmodified by the term “about” or “approximately” are approximations thatmay vary depending upon the desired properties sought to be obtained bythe present disclosure. At the very least, and not as an attempt tolimit the application of the doctrine of equivalents to the scope of theclaims, each numerical parameter should be construed in light of thenumber of significant digits and ordinary rounding approaches.

As used herein, the term “about” or “approximately” when referring to ameasurable value such as an amount, dimension, material parameter, andthe like, is meant to encompass variations of +/−10%, more preferably+/−5%, even more preferably, +/−1%, and still more preferably +/−0.1%from the specified value, as such variations are appropriate to performthe disclosed methods.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the invention are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspossible. Any numerical value, however, inherently contains certainerrors necessarily resulting from the standard deviation found in theirrespective testing and tolerance measurements. Every numerical rangegiven throughout this specification will include every narrowernumerical range that falls within such broader numerical range, as ifsuch narrower numerical ranges were all expressly written herein.

What is claimed is:
 1. A system for facilitating resuscitation,comprising: a resuscitation assembly comprising: a first electrodeassembly comprising a therapy side configured to sense ECG signals anddeliver a therapeutic shock and a first motion sensor, a secondelectrode assembly comprising a therapy side configured to sense ECGsignals and deliver a therapeutic shock and a second motion sensor andan identification component associated with the resuscitation assembly;processing circuitry operatively connected to the resuscitation assemblyand configured to identify the resuscitation assembly as one of apediatric or adult resuscitation assembly based on an identificationsignal produced by the identification component, receive and processsignals from at least one of the first and second motion sensors toestimate at least one of a compression depth and rate duringadministration of chest compressions, and receive and process ECGsignals from the first and second electrode assemblies and deliverelectrotherapy through the first and second electrode assemblies; and anoutput device for providing one or more chest compression parametersincluding at least one of the estimated compression depth and theestimated compression rate for a user, wherein the output device isconfigured to adjust presentation of the one or more chest compressionparameters based on whether the resuscitation assembly is identified aspediatric or adult, and wherein the processing circuitry is configuredto compare at least one of the estimated compression depth and theestimated compression rate to a desired range, and the output device isconfigured to display at least one of the estimated compression depthand the estimated compression rate and provide chest compressionprompting for the user when the resuscitation assembly is identified asadult and the output device is configured to display at least one of theestimated depth and the estimated rate without providing chestcompression prompting for the user when the resuscitation assembly isidentified as pediatric.
 2. The system of claim 1, wherein theprocessing circuitry is configured to determine a placement orientationof the first electrode assembly and the second electrode assembly on apatient based on a signal from at least one of the first motion sensorand the second motion sensor.
 3. The system of claim 2, wherein theprocessing circuitry is configured to determine whether the firstelectrode assembly is positioned on a first portion of the patient'sanatomy based on a signal from the first motion sensor and whether thesecond electrode assembly is positioned on a second portion of thepatient's anatomy in an anterior-posterior orientation based on a signalfrom the second motion sensor.
 4. The system of claim 2, wherein theprocessing circuitry is configured to determine whether the firstelectrode assembly is positioned on a first portion of the patient'sanatomy based on a signal from the second motion sensor and whether thesecond electrode assembly is positioned on a second portion of thepatient's anatomy in an anterior-anterior orientation based on a signalfrom the second motion sensor.
 5. The system of claim 2, wherein theprocessing circuitry is configured to: at least one of display on theoutput device the ECG signal and determine an orientation of a pacingvector; and adjust at least one of the displayed ECG signal and thepacing vector based on the determined placement orientation of the firstelectrode assembly and the second electrode assembly.
 6. The system ofclaim 1, wherein at least one of the first motion sensor and the secondmotion sensor is separable from the respective first or second electrodeassembly.
 7. The system of claim 1, wherein the estimated chestcompression depth is calculated by subtracting a distance traveled bythe second motion sensor from a distance traveled by the first motionsensor.
 8. The system of claim 1, wherein the first motion sensor isconfigured to produce a first signal representative of accelerationcaused by compressions and the second motion sensor is configured toproduce a second signal representative of acceleration due to movementon a compressible surface.
 9. The system of claim 1, wherein theprocessing circuitry and the output device are provided in an externaldefibrillator.
 10. The system of claim 1, wherein the identificationcomponent comprises at least one of a memory and a resistor from whichthe identification signal is based and the processing circuitry isconfigured to adjust a shock algorithm based on the identification ofthe resuscitation assembly as pediatric or adult.
 11. The system ofclaim 1, wherein at least one of the first electrode assembly and thesecond electrode assembly includes a flexible electrode layer includingthe therapy side, at least one of the first electrode assembly and thesecond electrode assembly includes a sensor housing configured toreceive one of the first motion sensor or the second motion sensor andattached to the electrode layer at an attachment region, and wherein atleast a portion of the electrode layer is constructed and arranged todeflect from the sensor housing at a location away from the attachmentregion such that the electrode layer substantially conforms to ananatomy of a patient.
 12. The system of claim 1, wherein theresuscitation assembly includes a cable extending from at least one ofthe first electrode assembly and the second electrode assembly towardthe processing circuitry, and the cable further includes additionalprocessing circuitry.
 13. The system of claim 12, wherein the additionalprocessing circuitry of the cable is configured to process signals fromthe first and second motion sensors by subtracting acceleration signalsfrom the first and second motion sensors.
 14. The system of claim 1,wherein the processing circuitry is configured to receive and processsignals from at least one of the first and second motion sensors toestimate release velocity, and the output device is configured toprovide guidance to the user based on the estimated release velocity.15. The system of claim 1, wherein the processing circuitry isconfigured to determine whether electrotherapy is required based on theprocessed ECG signals after receiving and processing the ECG signalsfrom the first and second electrode assemblies and prior to deliveringelectrotherapy through the first and second electrode assemblies. 16.The system of claim 1, wherein the processing circuitry is configured toadjust electrotherapy based on the identification of the resuscitationassembly as pediatric or adult.
 17. The system of claim 1, wherein theoutput device is configured to provide instructions to a user for asurface upon which a patient is positioned to be changed based oninformation sensed from the first and second motion sensors.
 18. Thesystem of claim 1, wherein the processing circuitry is configured toestimate an angle relative to a vertical axis of a patient at which auser is administering chest compressions during CPR based on the signalsreceived from the first and second motion sensors.
 19. The system ofclaim 1, wherein the processing circuitry is configured to estimate rateof ventilations applied to a patient based on a signal from at least oneof the first motion sensor and the second motion sensor.
 20. The systemof claim 19, wherein the output device is configured to provideinstructions to a user for administering ventilations to the patientbased on the estimated rate of ventilations.
 21. A system forfacilitating resuscitation, comprising: a resuscitation assemblycomprising: a first electrode assembly comprising a therapy sideconfigured to sense ECG signals and deliver a therapeutic shock and afirst motion sensor, a second electrode assembly comprising a therapyside configured to sense ECG signals and deliver a therapeutic shock anda second motion sensor, and an identification component associated withthe resuscitation assembly; processing circuitry operatively connectedto the resuscitation assembly and configured to identify theresuscitation assembly as one of a pediatric or adult resuscitationassembly based on an identification signal produced by theidentification component, receive and process signals from at least oneof the first and second motion sensors to estimate at least one of acompression depth and rate during administration of chest compressions,and receive and process ECG signals from the first and second electrodeassemblies and deliver electrotherapy through the first and secondelectrode assemblies; and an output device for providing one or morechest compression parameters including at least one of the estimatedcompression depth and the estimated compression rate for a user, whereinthe output device is configured to adjust presentation of the one ormore chest compression parameters based on whether the resuscitationassembly is identified as pediatric or adult, wherein at least one ofthe first motion sensor and the second motion sensor comprises anaccelerometer capable of measuring acceleration in multiple directions,wherein the processing circuitry is configured to estimate a differencein orientation between the first electrode assembly and the secondelectrode assembly based on a signal from at least one of the firstmotion sensor and the second motion sensor, and wherein the outputdevice is configured to provide instructions to a user for administeringchest compressions based on the estimation of orientation between thefirst and second electrode assemblies.
 22. The system of claim 21,wherein the processing circuitry is configured to determine a placementorientation of the first electrode assembly and the second electrodeassembly on a patient based on a signal from at least one of the firstmotion sensor and the second motion sensor.
 23. The system of claim 22,wherein the processing circuitry is configured to determine whether thefirst electrode assembly is positioned on a first portion of thepatient's anatomy based on a signal from the first motion sensor andwhether the second electrode assembly is positioned on a second portionof the patient's anatomy in an anterior-posterior orientation based on asignal from the second motion sensor.
 24. The system of claim 22,wherein the processing circuitry is configured to determine whether thefirst electrode assembly is positioned on a first portion of thepatient's anatomy based on a signal from the second motion sensor andwhether the second electrode assembly is positioned on a second portionof the patient's anatomy in an anterior-anterior orientation based on asignal from the second motion sensor.
 25. The system of claim 21,wherein at least one of the first motion sensor and the second motionsensor is separable from the respective first or second electrodeassembly.
 26. The system of claim 21, wherein the estimated chestcompression depth is calculated by subtracting a distance traveled bythe second motion sensor from a distance traveled by the first motionsensor.
 27. The system of claim 21, wherein the first motion sensor isconfigured to produce a first signal representative of accelerationcaused by compressions and the second motion sensor is configured toproduce a second signal representative of acceleration due to movementon a compressible surface.
 28. The system of claim 21, wherein theidentification component comprises at least one of a memory and aresistor from which the identification signal is based and theprocessing circuitry is configured to adjust a shock algorithm based onthe identification of the resuscitation assembly as pediatric or adult.29. The system of claim 21, wherein at least one of the first electrodeassembly and the second electrode assembly includes a flexible electrodelayer including the therapy side, at least one of the first electrodeassembly and the second electrode assembly includes a sensor housingconfigured to receive one of the first motion sensor or the secondmotion sensor and attached to the electrode layer at an attachmentregion, and wherein at least a portion of the electrode layer isconstructed and arranged to deflect from the sensor housing at alocation away from the attachment region such that the electrode layersubstantially conforms to an anatomy of a patient.
 30. The system ofclaim 21, wherein the resuscitation assembly includes a cable extendingfrom at least one of the first electrode assembly and the secondelectrode assembly toward the processing circuitry, and the cablefurther includes additional processing circuitry.
 31. The system ofclaim 30, wherein the additional processing circuitry of the cable isconfigured to process signals from the first and second motion sensorsby subtracting acceleration signals from the first and second motionsensors.
 32. The system of claim 21, wherein the processing circuitry isconfigured to receive and process signals from at least one of the firstand second motion sensors to estimate release velocity, and the outputdevice is configured to provide guidance to the user based on theestimated release velocity.
 33. The system of claim 21, wherein theprocessing circuitry is configured to determine whether electrotherapyis required based on the processed ECG signals after receiving andprocessing the ECG signals from the first and second electrodeassemblies and prior to delivering electrotherapy through the first andsecond electrode assemblies.
 34. The system of claim 21, wherein theprocessing circuitry is configured to adjust electrotherapy based on theidentification of the resuscitation assembly as pediatric or adult. 35.The system of claim 21, wherein the output device is configured toprovide instructions to a user for a surface upon which a patient ispositioned to be changed based on information sensed from the first andsecond motion sensors.
 36. The system of claim 21, wherein theprocessing circuitry is configured to estimate rate of ventilationsapplied to a patient based on a signal from at least one of the firstmotion sensor and the second motion sensor.
 37. The system of claim 36,wherein the output device is configured to provide instructions to auser for administering ventilations to the patient based on theestimated rate of ventilations.